Urban Water Use Efficiency Standards and Water Use Objective

The Water Conservation legislation of 2018 (SB 606 and AB 1668) established a new foundation for long-term improvements in urban water supplier conservation and drought planning in order to adapt to climate change and the longer more intense droughts in California. The legislation does not modify the current statewide goal of a 20 percent reduction in urban per capita water use by 2020 (i.e., suppliers' 2020 targets) as established by the Water Conservation Act of 2009 (SBX7-7).

The 2018 legislation applies to the actions of Department of Water Resources (Department), the State Water Resources Control Board (Water Board), and urban retail water suppliers; it does not set any standards or rules for individual customer water use.

AB 1668 (WC §10609.2(d)) requires that the long-term water use efficiency standards shall be set at a level designed so that urban retail water suppliers’ water use objectives (defined below), together with other demands excluded from the long-term standards such as Commercial, Industrial, and Institutional (CII) indoor water use and CII outdoor water use not connected to a dedicated landscape meter, would exceed the statewide 2020 conservation targets required pursuant to SBX7-7.

Urban Water Use Efficiency Standards

The legislation requires the Department, in coordination with the Water Board, to perform the necessary studies and investigations on:

  • The indoor residential water use and potential benefits and impacts associated with a changing standard and may jointly recommend to the Legislature an indoor residential water use standard that more appropriately reflects best practices (WC §10609.4(a))

And the legislation further requires the Department in coordination with the Water Board to develop recommendations and submit to the Water Board for adoption for:

  • Standards for outdoor residential water use (WC §10609.6).
  • Standards for CII outdoor irrigation of landscape areas with dedicated irrigation meters or equivalent technologies (WC §10609.8).
  • Appropriate variances for unique uses that have a significant effect (WC §10609.14).
  • Guidelines and methodologies that identify how an urban retail water supplier calculates its urban water use objective (WC §10609.16).
  • Performance measures for CII water use (WC §10609.10).

The Water Board, in coordination with the Department, is required to adopt long-term standards (WC §10609.2) and appropriate variances, guidelines, and methodologies for calculating urban water use objectives (WC §10609.2(e)). These standards, variances, and methodologies will become effective after June 2022, following the Water Board’s adoption of the recommendations through a public rulemaking process.

Urban Water Use Objective

Each year, urban retail water suppliers will have to calculate their ‘urban water use objective’ and assess whether they met their objective. This objective is based on an aggregate estimate of efficient water use for the previous year (calendar or fiscal) based on the adopted water use efficiency standards and local service area characteristics for that year (WC §10609.20).

The annual urban water use objective (WC §10609.20(c)) is the sum of:

  1. Aggregate estimated efficient indoor residential water use.
  2. Aggregate estimated efficient outdoor residential water use.
  3. Aggregate estimated efficient outdoor irrigation of landscape areas with dedicated irrigation meters or equivalent technology in connection with CII water use.
  4. Aggregate estimated efficient water losses.
  5. Aggregate estimated water use for approved variances.
  6. Potable reuse bonus incentive adjustment

By comparing the amount of water actually used in the previous year with the urban water use objective, urban retail water suppliers will be in a better position to help eliminate unnecessary use of water; that is, water used in excess of that needed to accomplish the intended beneficial use.(WC §10609(a)).

Recommendations and Reports

The Department has released the following report(s):

  1. Public Review Draft Report to the Legislature on the Results of Indoor Residential Water Use Studies

Draft Appendices available upon request. Please email wue@water.ca.gov.

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