California Code of Regulations › Title 23 - Waters › Division 3 - State Water Resources Control Board and Regional Water Quality Control Boards › Chapter 3.5 - Urban Water Use Efficiency and Conservation › Article 1 - Water Loss Performance Standards for Urban Retail Water Suppliers › Section 982 - Economic Model

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a)
				  Except as provided in subdivision (d), each urban retail water supplier's real
				  water loss standard shall be based on the formula identified in subdivision
				  (b), with the following inputs based on each supplier's own data or the default
				  value:
(1) Annual background leakage:
Annual background leakage shall be calculated as
					 follows:
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(2) Annual reported leakage:
Annual reported leakage shall be calculated as
					 follows:
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(3) Annual unreported leakage:
Annual unreported leakage shall be calculated by deducting
					 annual background leakage and annual reported leakage from average baseline
					 real loss.
(4) Months taken
				  to survey whole system:
Months taken to survey whole system shall be calculated by
					 dividing average length of mains by average leak detection survey
					 frequency.
(5) Part of
				  system:
Each part represents the amount of the system that can be
					 surveyed each month, such that the number of parts in a system is equal to the
					 number of months needed to survey the whole system.
(6) Unreported leakage per part of system:
Unreported leakage per part of system shall be calculated
					 by dividing annual unreported leakage by months taken to survey whole
					 system.
(7) Rate of rise of
				  leakage per part of system:
Rate of rise of leakage per part of system shall be
					 calculated by dividing rate of rise of leakage by months taken to survey whole
					 system.
(8) Monthly water
				  lost due to backlog of unreported leakage:
Monthly water lost due to backlog of unreported leakage
					 shall be calculated as follows:
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(9) Monthly water lost from rising leakage in
				  never surveyed parts of the system: Monthly water lost from rising leakage
				  prior to first leak survey shall be calculated as follows:
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(10) Monthly water lost from rising leakage
				  in previously surveyed parts of the system:
(A) Before one full leak detection survey has
				  been completed, the monthly water lost from rising leakage in previously
				  surveyed parts of the system shall be calculated as follows:
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(B) After the entire system has been surveyed
				  once, the monthly water lost from rising leakage in previously surveyed parts
				  of the system shall be calculated as follows:
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(11) Monthly unreported real loss with
				  intervention:
Monthly unreported real loss with intervention shall be the
					 sum of monthly water lost due to backlog of unreported leakage, monthly water
					 lost from rising leakage in never surveyed parts of the system, and monthly
					 water lost from rising leakage in previously surveyed parts of the
					 system.
(12) Monthly
				  unreported real loss without intervention:
Monthly unreported real loss without intervention shall be
					 calculated as follows:
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(13) Water saved in month of implementation:
Water saved in month of implementation shall be calculated
					 by deducting monthly unreported real loss with intervention from monthly
					 unreported real loss without intervention.
(14) Marginal avoided cost of water:
(A) At the beginning of 2022, the marginal
				  avoided cost of water shall be calculated as follows:
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(B) After 2022 begins, the marginal avoided
				  cost of water shall be calculated as follows:
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(15) Value of water loss reduced in each
				  month:
Value of water loss reduced in each month shall be
					 calculated as follows:
(water loss occuring without intervention - water loss
					 occuring with intervention) x Marginal cost of water in each time
					 step
(16) Present value of
				  water loss reduced each month:
Present value of water loss reduced each month shall be
					 calculated as follows:
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(17) Cost of leak detection during each
				  month:
Cost of leak detection during each month shall be the
					 product of average leak detection survey frequency in miles surveyed each month
					 and average cost of leak detection surveying per mile.
(18) Initial leakage level for part surveyed
				  each month:
(A) Before one full leak detection
				  survey has been completed, then unreported leakage per month shall be
				  calculated as follows:
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(B) After the entire system has been surveyed
				  once, unreported leakage per month shall be calculated as follows:
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(19) Average volume per leak per year:
Average volume per leak per year shall be calculated as
					 follows:
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(20) Volume of leakage from mains:
Volume of leakage from mains per leak per year shall be
					 calculated as follows:
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(21) Volume of leakage from service
				  connections:
Volume of leakage from service connections per leak per
					 year shall be calculated as follows:
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(22) Leaks found per part of the system:
Leaks found per part of the system is calculated for each
					 month as follows:
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(23) Cost of leak repair during each month:
Cost of leak repair during each month shall be calculated
					 as follows:
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(24) Total leak detection and repair cost for
				  each month:
Total leak detection and repair cost for each month shall
					 be the sum of cost of leak detection during each month plus cost of leak repair
					 during each month.
(25)
				  Present value of cost for each month:
Present value of cost for each month shall be calculated as
					 follows:
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(26) Present value of net benefit in month of
				  implementation:
Present value of net benefit in month of implementation
					 shall be calculated by deducting present value of cost for each month from
					 present value of benefit for each month.
(27) Present value of net benefit over 30
				  years:
Present value of net benefit over 30 years is the sum of
					 present value of net benefit in month of implementation summed from January 1,
					 2022, through December 31, 2051.
(28) Benefit to cost ratio until 2028:
The Benefit to cost ratio until 2028 is the sum of present
					 value of benefit for each month from January 2022 through December 2027 divided
					 by the sum of the present value of cost for each month from January 2022
					 through December 2027.