UWM Plan - Municipal Water District of Orange County

Section 2
Water Demand
Within a Regional Alliance, each retail water supplier will have an additional opportunity
to achieve compliance under both an individual target and a regional water use target.
• If the Regional Alliance meets its water use target on a regional basis, all agencies
in the alliance are deemed compliant.
• If the Regional Alliance fails to meet its water use target, each individual supplier
will have an opportunity to meet their water use targets individually.
Individual water suppliers in the Orange County 20x2020 Regional Alliance will state
their participation in the alliance, and include the regional 2015 and 2020 Urban Water
Use Targets in their individual UWMPs.
As the reporting agency for the Orange County 20x2020 Regional Alliance, MWDOC
has documented the calculations for the regional urban water use reduction targets.
MWDOC will also provide annual monitoring and reporting for the region on progress
toward the regional per capita water use reduction targets.
2.4.3. Steps to Calculate Regional Target
Water suppliers in a Regional Alliance are provided three options for calculating their
regional targets 2 . To preserve maximum flexibility, the Orange County 20x2020
Regional Alliance has selected the first option. There are two steps under this approach.
Under the first step, each water supplier in the Regional Alliance first calculates its
individual target in its retail UWMP as if it were complying individually. Under the
second step, the individual targets are weighted by each supplier’s population and
averaged over all members in the alliance to determine the regional water use target.
Step 1 - Retail Agency Compliance Targets
As described above, the first step in calculating a regional water use target is to determine
each water supplier’s individual target. DWR has established four target options for
urban retail water suppliers to choose from in calculating their water use reduction targets
under SBx7-7. The four options include:
• Option 1 requires a simple 20% reduction from the baseline by 2020 and 10
percent by 2015.
• Option 2 employs a budget-based approach by requiring an agency to achieve a
performance standard based on three metrics
o Residential indoor water use of 55 GPCD
o Landscape water use commiserate with Model Landscape Ordinance
2 Steps for calculating a Regional Alliance can be found in Methodology 9 from the Technical
Methodologies.
Municipal Water District of Orange County
2010 Regional Urban Water Management Plan
Final
2-9