BMP Target Method Option

1. BMP Target Method Option Peter Brostrom California Department of Water Resources Office of Water Use and Efficiency Branch October 15, 2010

2. Background • The 20x2020 Water Conservation Plan estimated that full implementation of the BMPs and code required water savings would result in 16% savings statewide. • Recognized as a potential approach that might meet the criteria for Method 4 required in the law.

3. Target Calculations • The level of BMP implementation is estimated for each BMP for the midpoint of the baseline period. • The water savings that would result from full implementation of each BMP are then calculated. • An agency that had almost fully implemented a BMP would have smaller savings requirements for the BMP • An agency that had done very little work on the BMP would have much larger savings requirements for the BMP

4. BMP Water Savings Calculator • DWR consultants developed a BMP water savings calculator that individual agencies can use to estimate the baseline implementation level and the water savings estimate for each BMP. • The calculator requires that individual agencies input a variety of baseline data such as toilets rebated, population growth, persons per households which is then used to model BMP implementation levels.

5. BMP Calculator estimates water savings for 6 BMPs. • BMP 1.2 Water Loss Control • BMP 1.3 Metering • BMP 3.1 Residential Assistance • BMP 3.2 Residential Landscape • BMP 4 CII • BMP 5.2 Landscape Budgets

6. To simplify the calculations, plumbing device saturation goals were established rather than following the BMP structure. The calculator estimates baseline saturation and water savings for the following plumbing devices: • Single family toilets • Multi family toilets • Residential washers • Residential showerheads

7. Statewide Adjustment Factor • Initially, DWR planned to use 20x2020 plan savings estimates with a 3% to 4% additional savings requirement to meet the 20% goal. • In September, targets were calculated for 12 agencies. Targets were lower than expected. • In October, DWR calculated targets for 20 more agencies chosen from a random sample. Average reduction was roughly 12.5%. Adjustment factor estimated at 7.5% • DWR will run 10 more random samples and will evaluate if more samples are needed. • DWR will also rerun the samples using 10 year baseline water use data.

8. Undue Hardship Clause • 10608.20 (b)(4)(f): Avoid placing an undue hardship on communities that have implemented conservation or taken actions to keep per capita water use low. • DWR recognizes there is a concern that there might be a very limited number of agencies who have significantly lowered their water use and may not be able to meet their water use targets without causing economic hardship to their communities.

9. DWR will consider establishing an appeals process that would allow a very limited number of agencies to adjust their water use target provided the following conditions are met: • Document that all BMPs and 20x2020 additional measures have been implemented. • Document that once all the BMPs and 2020 additional measures have been implemented, the conservation measures that an agency would have to implement to meet its water use target would be cost prohibitive and would cause economic hardship to water supplier’s community.