Outdoor Residential Use Standard

The Basics

  • The outdoor residential standard applies to both single family and multiple family housing units within a supplier’s service area.
  • The outdoor residential standard uses concepts like evapotranspiration, irrigation efficiency and landscape area (square feet) to calculate a water use budget for a supplier’s total residential landscapes.  The state will not provide/will not enforce landscape budgets for individual residential parcels.  More details provided below.
  • The state provided each supplier with residential landscape area (based on aerial imagery) for review. Total residential landscape area (in square feet) will be incorporated into a landscape water use equation/standard (provided by DWR) to produce a supplier level residential landscape budget in gallons.


October 2021

Landscape Objective Equation

At the October 25, 2021  stakeholder meeting, DWR released revised recommendations for the outdoor standard ETAF. See slide below for summary. 

Landscape Area Measurement

DWR reported that provisional landscape area measurement data was delivered to retail suppliers earlier this year. DWR received feedback from 56% of retail suppliers. Currently, landscape area for 395 of the 398 retail water suppliers have been finalized and will be delivered "over the next couple of weeks."


August 2021

Landscape Area Measurement

All suppliers should have received their landscape imagery data by now.  DWR requested feedback/changes on individual supplier’s landscape measurement data by June 30th. DWR has until August 30th to provide landscape measurement files back to those agencies that requested changes. 

Landscape Objective Equation

DWR has also released a proposed landscape budget equation that will be used to determine a supplier’s residential outdoor budget and is seeking input. There has been much conversation about whether to use irrigated or irrigable landscape measurements to apply to the budget equation. 

On June 30, at the Standards, Methodologies and Performance Measures Workgroup meeting, DWR proposed:

    • ET adjustment factor of 0.7
    • Irrigable not irrigated (INI) used as buffer (20% of INI) - (Option 5 below)


  • June 30 – Water suppliers LAM data correction/ request for ongoing data corrections
  • June 30 – Standards and Methodology Workgroup Meeting, DWR proposed:
    • ET adjustment factor of 0.7
    • Irrigable not irrigated (INI) used as buffer (20% of INI)
  • August 30 – Deadline for DWR review submitted adjustment requests and deliver final LAM data to the suppliers
  • August 25, 10:00 AM - 12:30 PM
  • October 25 - Standards, Methodologies and Performance Measures Workgroup
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