<SEC-DOCUMENT>0001292814-25-003200.txt : 20250902
<SEC-HEADER>0001292814-25-003200.hdr.sgml : 20250902
<ACCEPTANCE-DATETIME>20250902092127
ACCESSION NUMBER:		0001292814-25-003200
CONFORMED SUBMISSION TYPE:	20-F/A
PUBLIC DOCUMENT COUNT:		5
CONFORMED PERIOD OF REPORT:	20241231
FILED AS OF DATE:		20250902
DATE AS OF CHANGE:		20250902

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP
		CENTRAL INDEX KEY:			0001170858
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER SUPPLY [4941]
		ORGANIZATION NAME:           	01 Energy & Transportation
		EIN:				000000000
		STATE OF INCORPORATION:			D5
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		20-F/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31317
		FILM NUMBER:		251283283

	BUSINESS ADDRESS:	
		STREET 1:		RUA COSTA CARVALHO, 300
		STREET 2:		SAO PAULO
		CITY:			SP
		STATE:			D5
		ZIP:			05429-900
		BUSINESS PHONE:		011-55-11-3388-8000

	MAIL ADDRESS:	
		STREET 1:		RUA COSTA CARVALHO, 300
		STREET 2:		SAO PAULO
		CITY:			SP
		STATE:			D5
		ZIP:			05429-900
</SEC-HEADER>
<DOCUMENT>
<TYPE>20-F/A
<SEQUENCE>1
<FILENAME>sbsform20fa_2024.htm
<DESCRIPTION>20-F/A
<TEXT>
<HTML>
<HEAD>
<TITLE></TITLE>
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<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: black 0.5pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

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<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 4pt 0 0; text-align: center"><B>UNITED STATES </B></P>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Washington, D.C. 20549 </B></P>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>Amendment </B></P>

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<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>FORM 20-F/A </B></P>

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<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 12pt Times New Roman, Times, Serif; margin-top: 11pt; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 24.45pt"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD><TD><FONT STYLE="font-size: 9pt"><B>REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g)&nbsp;OF THE SECURITIES EXCHANGE ACT OF 1934
</B></FONT></TD></TR></TABLE>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>OR </B></P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 12pt Times New Roman, Times, Serif; margin-top: 11pt; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 24.45pt"><FONT STYLE="font-family: Wingdings; font-size: 10pt">x</FONT></TD><TD><FONT STYLE="font-size: 9pt"><B>ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 </B></FONT></TD></TR></TABLE>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>For the fiscal year ended December&nbsp;31,
2024 </B></P>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>OR </B></P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 12pt Times New Roman, Times, Serif; margin-top: 11pt; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 24.45pt"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD><TD><FONT STYLE="font-size: 9pt"><B>TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 </B></FONT></TD></TR></TABLE>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>OR </B></P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 12pt Times New Roman, Times, Serif; margin-top: 11pt; margin-bottom: 0"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 24.45pt"><FONT STYLE="font-family: Wingdings; font-size: 10pt">&uml;</FONT></TD><TD><FONT STYLE="font-size: 9pt"><B>SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 </B></FONT></TD></TR></TABLE>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>Commission File Number: 001-31317 </B></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Companhia de Saneamento B&aacute;sico do Estado
de S&atilde;o Paulo- SABESP</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">(Exact name of Registrant as specified in its charter)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Basic Sanitation Company of the State of S&atilde;o
Paulo- SABESP</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">(Translation of the Registrant&#8217;s name into English)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Federative Republic of Brazil</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">(Jurisdiction of incorporation or organization)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Rua Costa Carvalho, 300</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>05429-900&nbsp;S&atilde;o Paulo, SP,&nbsp;Brazil</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0.05pt 0 0; text-align: center">(Address of principal executive offices)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Daniel Szlak</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>dri@sabesp.com.br&nbsp;(+55 11&nbsp;3388 8000)</B></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 34%; padding-right: 5.4pt; padding-left: 5.4pt">
    <P STYLE="font: 8pt Times New Roman, Times, Serif; margin: 0 0 4pt; text-align: center; border-bottom: Black 0.5pt solid">Title of each
    class</P></TD>
    <TD STYLE="width: 33%; padding-right: 5.4pt; padding-left: 5.4pt">
    <P STYLE="font: 8pt Times New Roman, Times, Serif; margin: 0 0 4pt; text-align: center; border-bottom: Black 0.5pt solid">Trading Symbol</P></TD>
    <TD STYLE="width: 33%; padding-right: 5.4pt; padding-left: 5.4pt">
    <P STYLE="font: 8pt Times New Roman, Times, Serif; margin: 0 0 4pt; text-align: center; border-bottom: Black 0.5pt solid">Name of each
    exchange on which registered</P></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center"><FONT STYLE="font-size: 8pt"><B>Common Shares, without par value</B></FONT></TD>
    <TD STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center"><FONT STYLE="font-size: 8pt"><B>Not traded</B></FONT></TD>
    <TD STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center"><FONT STYLE="font-size: 8pt"><B>New York Stock Exchange*</B></FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD ROWSPAN="3" STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center"><FONT STYLE="font-size: 8pt"><B>American Depositary Shares, evidenced by American Depositary Receipts, each representing one Common Share</B></FONT></TD>
    <TD STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center"><FONT STYLE="font-size: 8pt"><B>SBS</B></FONT></TD>
    <TD ROWSPAN="3" STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center"><FONT STYLE="font-size: 8pt"><B>New York Stock Exchange </B></FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font: 12pt Times New Roman, Times, Serif; padding-right: 5.4pt; padding-bottom: 4pt; padding-left: 5.4pt; text-align: center">&nbsp;</TD></TR>
  </TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Rua Costa Carvalho, 300&nbsp;05429-900&nbsp;S&atilde;o
Paulo, SP,&nbsp;Brazil</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Securities registered or to be registered pursuant
to Section 12(b) of the Act:</B></P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0"><FONT STYLE="font-size: 10pt">* </FONT><FONT STYLE="font-size: 8pt">Shares
are not listed for trading, but only in connection with the registration of American Depositary Receipts pursuant to the requirements
of the New York Stock Exchange.&nbsp;</FONT></P>




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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>Securities registered or to be registered
pursuant to Section&nbsp;12(g) of the Act: None. </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0; text-align: center"><B>Securities for which there is a reporting
obligation pursuant to Section&nbsp;15(d) of the Act: None. </B></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">The number of outstanding shares of each of the issuer's classes
of capital or common stock as of December&nbsp;31, 2024 was:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">683,509,868&nbsp;Shares of Common Stock</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">1 Share of Preferred Stock</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">Indicate by check mark if the registrant is a well-known seasoned
issuer, as defined in Rule 405 of the Securities Act.&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">x</FONT>&nbsp;&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;&nbsp;No</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">If this report is an annual or transition report, indicate by check
mark if the registrant is not required to file reports pursuant to Section&nbsp;13 or 15(d) of the Securities Exchange Act of 1934.&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;&nbsp;
<FONT STYLE="font-family: Wingdings">x</FONT>&nbsp;&nbsp;No</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">Indicate by checkmark whether the registrant (1)&nbsp;has filed
all reports required to be filed by Section&nbsp;13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or
for such shorter period that the registrant was required to file such reports), and (2)&nbsp;has been subject to such filing requirements
for the past 90 days&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">x</FONT>&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;&nbsp; <FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;No</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">Indicate by check mark whether the registrant has submitted electronically
every Interactive Data File to be submitted pursuant to Rule 405 of Regulation S-T (&sect;232.405 of this chapter) during the preceding
12 months (or for such shorter period that the registrant was required to submit and post such files).&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">x</FONT>&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;No</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Indicate by check mark whether the registrant is a large accelerated filer,
an accelerated filer, a non-accelerated filer, or an emerging growth company. See the definitions of &#8220;large accelerated filer,&#8221;
&#8220;accelerated filer,&#8221; and &#8220;emerging growth company&#8221; in Rule 12b-2 of the Exchange Act. (Check one):</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 12pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR>
    <TD STYLE="vertical-align: top; width: 24%; padding-right: 0.7pt; padding-left: 0.7pt"><FONT STYLE="font-size: 10pt">Large accelerated filer <FONT STYLE="font-family: Wingdings">x</FONT></FONT></TD>
    <TD STYLE="vertical-align: bottom; width: 2%; padding-right: 0.7pt; padding-left: 0.7pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; width: 20%; padding-right: 0.7pt; padding-left: 0.7pt"><FONT STYLE="font-size: 10pt">Accelerated filer <FONT STYLE="font-family: Wingdings">o</FONT></FONT></TD>
    <TD STYLE="vertical-align: bottom; width: 1%; padding-right: 0.7pt; padding-left: 0.7pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; width: 23%; padding-right: 0.7pt; padding-left: 0.7pt"><FONT STYLE="font-size: 10pt">Non-accelerated filer <FONT STYLE="font-family: Wingdings">o</FONT></FONT></TD>
    <TD STYLE="vertical-align: top; width: 2%; padding-right: 0.7pt; padding-left: 0.7pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; width: 28%; padding-right: 0.7pt; padding-left: 0.7pt"><FONT STYLE="font-size: 10pt">Emerging growth company&nbsp;<FONT STYLE="font-family: Wingdings">o</FONT></FONT></TD></TR>
  </TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">If an emerging growth company that prepares its financial statements in
accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period for complying
with any new or revised financial accounting standards* provided pursuant to Section 13(a) of the Exchange Act. <FONT STYLE="font-family: Wingdings">o</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">*The term &#8216;&#8216;new or revised financial accounting standard&#8217;&#8217;
refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.</P>

<P STYLE="font: 9pt Times New Roman, Times, Serif; margin: 0"><FONT STYLE="background-color: white"><BR>
Indicate by check mark whether the registrant has filed a report on and attestation to its management&#8217;s assessment of the effectiveness
of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered
public accounting firm that prepared or issued its audit report.&nbsp;<FONT STYLE="font-family: Segoe UI Symbol,sans-serif">&#9746;</FONT></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">Indicate by check mark which basis of accounting the registrant
has used to prepare the financial statements included in this filing:</P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

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  <TR>
    <TD STYLE="width: 19%">&nbsp;</TD>
    <TD STYLE="width: 64%">&nbsp;</TD>
    <TD STYLE="width: 17%">&nbsp;</TD></TR>
  <TR>
    <TD STYLE="vertical-align: top; font: 12pt Times New Roman, Times, Serif; padding-left: 12pt; text-indent: -12pt"><FONT STYLE="font-size: 10pt">U.S.&nbsp;GAAP&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT></FONT></TD>
    <TD STYLE="vertical-align: bottom; font: 12pt Times New Roman, Times, Serif; text-align: center"><FONT STYLE="font-size: 9pt; background-color: white">International Financial Reporting Standards&nbsp;as issued by the International Accounting Standards Board</FONT><FONT STYLE="font-size: 10pt">&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">x</FONT></FONT></TD>
    <TD STYLE="white-space: nowrap; vertical-align: top; font: 12pt Times New Roman, Times, Serif; padding-bottom: 1pt"><FONT STYLE="font-size: 10pt">&#9;Other&nbsp;&nbsp;&#9;<FONT STYLE="font-family: Wingdings">&uml;</FONT></FONT></TD></TR>
  </TABLE>
<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 11pt 0 0"><FONT STYLE="font-size: 9pt; background-color: white">If &#8220;Other&#8221;
has been checked in response to the previous question,&nbsp;</FONT><FONT STYLE="font-size: 10pt">indicate by check mark which financial
statement item the registrant has elected to follow. &nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;Item&nbsp;17&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;Item&nbsp;18
</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 11pt 0 0">If this is an annual report, indicate by check mark whether the
registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act.). &nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">&uml;</FONT>&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;&nbsp;<FONT STYLE="font-family: Wingdings">x</FONT>&nbsp;&nbsp;No</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Explanatory Note &#8212; Amendment</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: justify; margin-right: 0; margin-left: 0">This amendment (&#8220;Amendment
No. 1&#8221;) to the Annual Report on Form&nbsp;20-F&nbsp;of <FONT STYLE="background-color: white">Companhia de Saneamento B&aacute;sico
do Estado de S&atilde;o Paulo-SABESP </FONT>(&#8220;Sabesp&#8221;) for the year ended December&nbsp;31, 2024 filed on April 30, 2025 (the
&#8220;Original Annual Report&#8221;)&nbsp;is being filed solely to: (i) rectify the total estimated amount of claims described in Item
8.A related to our legal proceedings, and (ii) add legal proceeding No. 2263215-97.2021.8.26.0000 to the legal proceedings described in
Item 8.A. Consolidated Financial Statements and Other Financial Information&#8212;Legal Proceedings&#8212;Civil Claims (including Customer
and Supplier Claims).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: justify; margin-right: 0; margin-left: 0">This Amendment No. 1 rectifies
the total estimated amount of claims described in Item 8.A related to our legal proceedings, from &#8220;R$167.7 billion (net of R$24.6
million in court deposits)&#8221;, to &#8220;R$24.7 billion (net of R$167.7 million in court deposits)&#8221;.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: justify; margin-right: 0; margin-left: 0">This Amendment No. 1 adds to
the legal proceedings described in Item 8.A. Consolidated Financial Statements and Other Financial Information&#8212;Legal Proceedings&#8212;Civil
Claims (including Customer and Supplier Claims):</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 12pt Times New Roman, Times, Serif"><TR STYLE="vertical-align: top">
<TD STYLE="width: 18pt"></TD><TD STYLE="width: 18pt"><FONT STYLE="font-family: Symbol; font-size: 10pt">&middot;</FONT></TD><TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">&quot;<B>Lawsuit No. 2263215-97.2021.8.26.0000 filed by Subcondominio Eldorado
Business Tower (&#8220;Eldorado&#8221;) (Main File No. 1011195-34.2020.8.26.0011):</B> Eldorado is seeking declaratory relief, combined
with a claim for restitution of undue payments, asserting its alleged right to revise the charging scheme applied to commercial users.
The claim was dismissed by the court of first instance. Eldorado subsequently (i) filed an appeal seeking to overturn the judgment; and
(ii) filed to initiate an Incident of Repetitive Demands (<I>Incidente de Resolu&ccedil;&atilde;o de Demandas Repetitivas </I>- IRDR),
a procedural mechanism aimed at harmonizing case law on recurring legal issues. Eldorado&#8217;s appeal was dismissed, and the decision
became final (<I>res judicata</I>). The IRDR was accepted and was likewise resolved in our favor. In response, Eldorado filed a Special
Appeal (to the Superior Court of Justice - STJ) and an Extraordinary Appeal (to the Supreme Federal Court - STF). Both of which are currently
pending review before the Higher Courts as of the date of this Amendment No. 1. As of the date of this Amendment No. 1, the amount involved
in the lawsuit cannot be reliably estimated. The risk of loss is currently assessed as possible.&quot;</FONT></TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: justify; margin-right: 0; margin-left: 0">This Amendment No. 1 speaks
as of the initial filing date of the Original Annual Report unless otherwise indicated. Other than as expressly set forth above, no part
of the Original Annual Report is being amended. Accordingly, other than as discussed above, this Amendment No. 1 does not purport to amend,
update or restate any other information or disclosure included in the Original Annual Report or reflect any events that have occurred
after the initial filing date of the Original Annual Report. As a result, the Original Annual Report continues to speak as of April 30,
2024 or, to the extent applicable, such other date in respect of the Original Annual Report as may be indicated in the Original Annual
Report.However, this Amendment No. 1 includes Exhibits 12.1, 12.2, 13.1 and 13.2, new certifications by Sabesp&#8217;s Chief Executive
Officer and Chief Financial Officer as required by Rule 12b-15.</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 2.75pt 73.95pt 0 74.75pt; text-align: center"><FONT STYLE="letter-spacing: -0.05pt"><B>ITEM&nbsp;19.
EXHIBITS</B></FONT></P>

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    <TD STYLE="width: 9%; padding-bottom: 6pt; padding-left: 30.6pt; text-indent: -30.6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex12-1.htm">12.1*</A></FONT></TD>
    <TD STYLE="width: 91%; padding-bottom: 6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex12-1.htm">Certification of Carlos Augusto Leone Piani, Chief Executive Officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.</A></FONT></TD></TR>
  <TR STYLE="vertical-align: top; background-color: white">
    <TD STYLE="padding-bottom: 6pt; padding-left: 30.6pt; text-indent: -30.6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex12-2.htm">12.2*</A></FONT></TD>
    <TD STYLE="padding-bottom: 6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex12-2.htm">Certification of Daniel Szlak, Chief Financial Officer and Investor Relations Officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.</A></FONT></TD></TR>
  <TR STYLE="vertical-align: top; background-color: #CCEEFF">
    <TD STYLE="padding-bottom: 6pt; padding-left: 30.6pt; text-indent: -30.6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex13-1.htm">13.1*</A></FONT></TD>
    <TD STYLE="padding-bottom: 6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex13-1.htm">Certification of Carlos Augusto Leone Piani, Chief Executive Officer, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes- Oxley Act of 2002.</A></FONT></TD></TR>
  <TR STYLE="vertical-align: top; background-color: white">
    <TD STYLE="padding-bottom: 6pt; padding-left: 30.6pt; text-indent: -30.6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex13-2.htm">13.2*</A></FONT></TD>
    <TD STYLE="padding-bottom: 6pt"><FONT STYLE="font-size: 10pt"><A HREF="ex13-2.htm">Certification of Daniel Szlak, Chief Financial Officer and Investor Relations Officer, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.</A></FONT></TD></TR>
  </TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;*Filed herewith.</P>


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<P STYLE="font: 1pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>SIGNATURES </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 12pt 0 0">The registrant hereby certifies that it meets all of the requirements
for filing on Form 20-F/A or amendment thereto and that it has duly caused and authorized the undersigned to sign this Amendment No. 1
to its Annual Report on its behalf.</P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>COMPANHIA DE SANEAMENTO B&Aacute;SICO DO ESTADO DE S&Atilde;O PAULO
- SABESP</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 12pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR>
    <TD STYLE="width: 43%; padding-bottom: 6pt">&nbsp;</TD>
    <TD STYLE="width: 57%; padding-bottom: 6pt">&nbsp;</TD>
    </TR>
  <TR>
    <TD STYLE="vertical-align: top; padding-right: 24pt; padding-bottom: 6pt"><FONT STYLE="font-size: 10pt">By:</FONT></TD>
    <TD STYLE="vertical-align: bottom; border-bottom: black 1pt solid; padding-bottom: 6pt">&nbsp;</TD>
    </TR>
  <TR>
    <TD STYLE="padding-bottom: 6pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Name: Carlos Augusto Leone Piani</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Title: Chief Executive Officer</P></TD>
    </TR>
  <TR>
    <TD STYLE="vertical-align: top; padding-bottom: 6pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom; padding-bottom: 6pt">&nbsp;</TD>
    </TR>
  <TR>
    <TD STYLE="vertical-align: top; padding-bottom: 6pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom; padding-bottom: 6pt">&nbsp;</TD>
    </TR>
  <TR>
    <TD STYLE="vertical-align: top; padding-right: 24pt; padding-bottom: 6pt"><FONT STYLE="font-size: 10pt">By:</FONT></TD>
    <TD STYLE="vertical-align: bottom; border-bottom: black 1pt solid; padding-bottom: 6pt">&nbsp;</TD>
    </TR>
  <TR>
    <TD STYLE="padding-bottom: 6pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Name: Daniel Szlak</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Title: Chief Financial Officer and Investor Relations Officer</P></TD>
    </TR>
  </TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">Date:&nbsp;&nbsp;August
27,<B>&nbsp;</B>2025&nbsp;&nbsp;</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: center; background-color: white"><B>CERTIFICATION</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">I, Carlos Augusto
Leone Piani, certify that:</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 12pt Times New Roman, Times, Serif; width: 100%">
  <TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">1.</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">I have reviewed this annual report on Form 20-F, as amended by Amendment No.1, of Companhia de Saneamento B&aacute;sico do Estado de S&atilde;o Paulo &#8211; Sabesp;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">2.</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">3.</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">Based on my knowledge, the financial statements and other financial information included in this report fairly present in all material respects the financial condition, results of operations and cash flows of the company as of, and for, the periods presented in this report;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt">4.</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">The company&#8217;s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the company and have:&nbsp;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%">&nbsp;</TD>
    <TD STYLE="width: 1%"><FONT STYLE="font-size: 10pt">a.</FONT></TD>
    <TD STYLE="width: 96%; text-align: justify"><FONT STYLE="font-size: 10pt">designed such disclosure controls and procedures or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the company, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">b.</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">c.</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">evaluated the effectiveness of the company&#8217;s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures as of the end of the period covered by this report based on evaluation; and</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">d.</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">disclosed in this report any change in the company&#8217;s internal control over financial reporting that occurred during the period covered by the annual report that has materially affected, or is reasonably likely to materially affect, the company&#8217;s internal control over financial reporting.</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">5.</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">The company&#8217;s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the company&#8217;s auditors and to the audit committee of the company&#8217;s board of directors (or persons performing the equivalent function):</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">a.</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the company&#8217;s ability to record, process, summarize and report financial information; and</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">b.</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">any fraud, whether or not material, that involves management or other employees who have a significant role in the company&#8217;s internal control over financial reporting.</FONT></TD></TR>
  </TABLE>
<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white"><FONT STYLE="font-size: 10pt">&nbsp;</FONT>&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">Date:&nbsp;&nbsp;August
27,<B>&nbsp;</B>2025</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">By:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Name:&nbsp; &nbsp; Carlos
Augusto Leone Piani</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Title:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Chief
Executive Officer</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: center; background-color: white"><B>CERTIFICATION</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">I, Daniel Szlak, certify
that:</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 12pt Times New Roman, Times, Serif; width: 100%">
  <TR>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">1.</FONT></TD>
    <TD COLSPAN="2" STYLE="vertical-align: top; text-align: justify"><FONT STYLE="font-size: 10pt">I have reviewed this annual report on Form 20-F, as amended by Amendment No.1, of Companhia de Saneamento B&aacute;sico do Estado de S&atilde;o Paulo &#8211; Sabesp;</FONT></TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">2.</FONT></TD>
    <TD COLSPAN="2" STYLE="vertical-align: top; text-align: justify"><FONT STYLE="font-size: 10pt">Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;</FONT></TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">3.</FONT></TD>
    <TD COLSPAN="2" STYLE="vertical-align: top; text-align: justify"><FONT STYLE="font-size: 10pt">Based on my knowledge, the financial statements and other financial information included in this report fairly present in all material respects the financial condition, results of operations and cash flows of the company as of, and for, the periods presented in this report;</FONT></TD>
    <TD>&nbsp;</TD></TR>
  <TR>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">4.</FONT></TD>
    <TD COLSPAN="2" STYLE="vertical-align: top; text-align: justify"><FONT STYLE="font-size: 10pt">The company&#8217;s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the company and have:&nbsp;</FONT></TD>
    <TD>&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">a)</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">designed such disclosure controls and procedures or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the company, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">b)</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">c)</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">evaluated the effectiveness of the company&#8217;s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures as of the end of the period covered by this report based on evaluation; and</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">d)</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">disclosed in this report any change in the company&#8217;s internal control over financial reporting that occurred during the period covered by the annual report that has materially affected, or is reasonably likely to materially affect, the company&#8217;s internal control over financial reporting.</FONT></TD></TR>
  <TR>
    <TD STYLE="vertical-align: top"><FONT STYLE="font-size: 10pt">5.</FONT></TD>
    <TD COLSPAN="2" STYLE="vertical-align: top; text-align: justify"><FONT STYLE="font-size: 10pt">The company&#8217;s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the company&#8217;s auditors and to the audit committee of the company&#8217;s board of directors (or persons performing the equivalent function):</FONT></TD>
    <TD>&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">a)</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the company&#8217;s ability to record, process, summarize and report financial information; and</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt">b)</FONT></TD>
    <TD COLSPAN="2" STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">any fraud, whether or not material, that involves management or other employees who have a significant role in the company&#8217;s internal control over financial reporting.</FONT></TD></TR>
  <TR>
    <TD STYLE="width: 1%">&nbsp;</TD>
    <TD STYLE="width: 1%">&nbsp;</TD>
    <TD STYLE="width: 97%">&nbsp;</TD>
    <TD STYLE="width: 1%">&nbsp;</TD></TR>
  </TABLE>
<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white"><FONT STYLE="font-size: 10pt">&nbsp;</FONT>&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">Date:&nbsp;&nbsp;August
27, 2025</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">By:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Name:&nbsp; &nbsp; Daniel
Szlak</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">Title:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Chief
Financial Officer and Investor Relations Officer</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: center; background-color: white"><B>CERTIFICATION PURSUANT
TO 18 U.S.C. SECTION 1350,<BR>
AS ADOPTED PURSUANT TO<BR>
SECTION 906 OF THE U.S. SARBANES-OXLEY ACT OF 2002</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">In connection with
the Annual Report of Companhia de Saneamento B&aacute;sico do Estado de S&atilde;o Paulo &#8211; Sabesp (the &#8220;Company&#8221;) on
Form 20-F, as amended by Amendment No.1, for the fiscal year ended December 31, 2024, as filed with the U.S. Securities and Exchange Commission
on the date hereof (the &#8220;Report&#8221;), I, Carlos Augusto Leone Piani, Chief Executive Officer, certify, pursuant to 18 U.S.C.
section 1350, as adopted pursuant to section 906 of the U.S. Sarbanes Oxley Act of 2002, that to the best of my knowledge:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">(i)&#9;the Report
fully complies with the requirements of section 13(a) or 15(d) of the U.S. Securities Exchange Act of 1934; and</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">(ii)&#9;the information
contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">Date:&nbsp;&nbsp;August
27, 2025</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">By:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Name:&nbsp; &nbsp;&nbsp;Carlos
Augusto Leone Piani</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Title:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Chief
Executive Officer</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: center; background-color: white"><B>CERTIFICATION PURSUANT
TO 18 U.S.C. SECTION 1350,<BR>
AS ADOPTED PURSUANT TO<BR>
SECTION 906 OF THE U.S. SARBANES-OXLEY ACT OF 2002</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">In connection with
the Annual Report of Companhia de Saneamento B&aacute;sico do Estado de S&atilde;o Paulo &#8211; Sabesp (the &#8220;Company&#8221;) on
Form 20-F, as amended by Amendment No.1, for the fiscal year ended December 31, 2024, as filed with the U.S. Securities and Exchange Commission
on the date hereof (the &#8220;Report&#8221;), I, Daniel Szlak, Chief Financial Officer and Investor Relations Officer, certify, pursuant
to 18 U.S.C. section 1350, as adopted pursuant to section 906 of the U.S. Sarbanes Oxley Act of 2002, that to the best of my knowledge:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">(i)&#9;the Report
fully complies with the requirements of section 13(a) or 15(d) of the U.S. Securities Exchange Act of 1934; and</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">(ii)&#9;the information
contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 10pt; text-align: justify; background-color: white">Date:&nbsp;&nbsp;August
27, 2025</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">By:&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Name:&nbsp; &nbsp; Daniel
Szlak</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; background-color: white">Title:&nbsp; &nbsp;&nbsp;&nbsp;
Chief Financial Officer and Investor Relations Officer</P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 2.75pt 4.9pt 0 0; text-align: right">&nbsp;</P>


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