C. Gas utilities subject to the jurisdiction of the commission solely with respect to safety are not subject to any assessment.

D. The commission may correct any errors in the assessments by means of a credit or debit to the following year's assessment rather than reassessing all utilities in the current year.

E. The commission may exempt utilities with annual intrastate gross operating revenues under $50,000 from assessments under this section.

F.__For water utilities that do not have a customer metering program, the commission shall determine water sales to be 90% of total water production.

Sec. 2. 35-A MRSA §116, sub-§8, as amended by PL 2001, c. 28, §1, is further amended to read:

8. Public Advocate assessment. Every utility subject to assessment under this section is subject to an additional annual assessment on its intrastate gross operating revenues to produce sufficient revenue for expenditures allocated by the Legislature for operating the Office of Public Advocate. The Public Advocate shall determine the percent revenue assessment required from each transmission and distribution, gas, telephone, water and ferry utility group based on the pro rata share of the intrastate gross operating revenues from each respective utility group.__The Public Advocate shall base the assessment for each individual transmission and distribution, gas, telephone and ferry utility on the pro rata share of each utility's intrastate gross operating revenue in conjunction with the percent revenue assessment determined for each respective utility group.__The Public Advocate shall base the assessment for each individual water utility on the pro rata share of the utility's metered water sales in thousands of gallons sold pursuant to the percent revenue assessment determined for each respective utility group. The revenues produced from this assessment are transferred to the Public Advocate Regulatory Fund and may only be used to fulfill the duties specified in chapter 17. The assessments charged to utilities under this subsection are considered just and reasonable operating costs for rate-making purposes. The Public Advocate shall develop a method of accounting for staff time within the Office of Public Advocate. All professional and