Income Taxes:	6 Months Ended
Jun. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes: As a regulated utility, GSWC treats certain temporary differences as flow-through adjustments in computing its income tax provision consistent with the income tax approach approved by the CPUC for ratemaking purposes. Flow-through adjustments increase or decrease tax expense in one period, with an offsetting decrease or increase occurring in another period. Giving effect to these temporary differences as flow-through adjustments typically results in a greater variance between the effective tax rate (“ETR”) and the statutory federal income tax rate in any given period than would otherwise exist if GSWC were not required to account for its income taxes as a regulated enterprise. The GSWC ETRs deviated from the statutory rate primarily due to state taxes and differences between book and taxable income that are treated as flow-through adjustments in accordance with regulatory requirements (principally plant-, rate-case- and compensation-related items), as well as permanent items. Changes in Tax Law: In January 2013, the American Taxpayer Relief Act of 2012 extended 50% bonus depreciation for qualifying property through 2013. Although this change in law reduces AWR’s current taxes payable, it does not reduce its total income tax expense or ETR.

Income Taxes:

6 Months Ended

Jun. 30, 2013

Income Taxes:

As a regulated utility, GSWC treats certain temporary differences as flow-through adjustments in computing its income tax provision consistent with the income tax approach approved by the CPUC for ratemaking purposes. Flow-through adjustments increase or decrease tax expense in one period, with an offsetting decrease or increase occurring in another period. Giving effect to these temporary differences as flow-through adjustments typically results in a greater variance between the effective tax rate (“ETR”) and the statutory federal income tax rate in any given period than would otherwise exist if GSWC were not required to account for its income taxes as a regulated enterprise. The GSWC ETRs deviated from the statutory rate primarily due to state taxes and differences between book and taxable income that are treated as flow-through adjustments in accordance with regulatory requirements (principally plant-, rate-case- and compensation-related items), as well as permanent items.

Changes in Tax Law:

In January 2013, the American Taxpayer Relief Act of 2012 extended 50% bonus depreciation for qualifying property through 2013. Although this change in law reduces AWR’s current taxes payable, it does not reduce its total income tax expense or ETR.