6. True-Up of Interim Rates Adopted in D.07-06-028

In D.07-06-028, we found it in the public interest to grant interim rate relief to Cal Water for the eight districts in this GRC proceeding. Consistent with Section 455.2, the interim rate increase is based on the rate of inflation as compared to existing rates for each district, is subject to refund, and will be adjusted upward or downward, back to July 1, 2007, based on the final rates adopted by the Commission in this decision.¹⁰⁰

Based on our decision today, there will be a surcharge for each district for the period since July 1, 2007. Cal Water should calculate this surcharge amount based on the actual loss or gain in each district's revenue, determined by applying the rate differential to the actual quantities of water sales and the actual number of customers.¹⁰¹ Cal Water should recover the surcharge for each district over the following 12 months and should earn interest at the 90-day commercial paper rate on the surcharge balance.

¹⁰⁰ The rate of inflation is to be calculated using the most recent Consumer Price Index maintained by the U.S. Department of Labor.

¹⁰¹ Westlake District's reclaimed water usage is not subject to the interim rate or the surcharge. A refund should be provided for any interim rate increase paid.