About 40% of the water Californians use at home is used outdoors. Large water savings can be gained by efficient landscape design, installation, management, and maintenance. This is accomplished by choosing climate adapted plants, improving soil conditions, using, and maintaining high efficiency irrigation equipment and managing the irrigation schedule to fit the plants water needs as they are influenced by local climate. To increase water efficiency and better use a valuable resource, rainwater and stormwater collection and graywater and recycled water can replace or augment potable water use in landscapes.
New development and retrofitted landscape water efficiency standards are governed by the Model Water Efficient Landscape Ordinance (MWELO). The MWELO is also referenced by Title 24, Part 11, Chapters 4 and 5 CalGreen Building Code. All local agencies must adopt, implement, and enforce the MWELO or a local Water Efficient Landscape Ordinance (WELO) that is at least as effective as the MWELO. Usually, local agencies that adopt WELOs create a more stringent ordinance than MWELO.
The purpose of water efficient landscape ordinances is to not only increase water efficiency but to improve environmental conditions in the built environment. Landscaping should be valued beyond the aesthetic because landscapes replace habitat lost to development and provide many other related benefits such as improvements to public health and quality of life, climate change mitigation, energy and materials conservation and increased property values.
Local agencies are required to report on implementation annually by January 31 of each year to DWR’s Water Use Efficiency Branch using the WUEdata Portal.
DWR worked with local agencies, water suppliers, landscape industry groups, and public interested parties to prepare the current updated MWELO. To join a list of MWELO interested parties or to join the active Landscape Statewide Advisory Group (LSAG) email Landscape@water.ca.gov with either “MWELO interested party” or “Join LSAG” in the subject line.
Rulemaking Announcements
Final MWELO Regulations and Appendices – Approved by the Office of Administrative Law (OAL) on and effective starting January 2, 2025:
MWELO Regulations and Appendices (PDF) Note: Changes are shown in single underline and strikeout.
MWELO Regulations (California Code of Regulations) Note: Anticipated to be updated online by February 2025
Updated Information Digest
Final Statement of Reasons (FISOR)
CEQA Notice of Exemption (NOE)
Initial Notice Documents (60-Day comment period)
On November 17, 2023, DWR released the originally proposed amendments to the MWELO regulation and marked the official start of the public comment period provided under California law. Public comments were received by DWR during a hybrid in-person and virtual hearing on January 9, 2024. Interested parties were encouraged to submit comments on the proposed regulations by January 16, 2024.
Text of the proposed MWELO amendments
Notice of Proposed Rulemaking
Initial Statement of Reasons (ISOR)
Standard Form 399 and Attachment
Informational Exhibits A, B, and C
Subsequent modifications to the proposed MWELO amendments were announced by DWR in 2024 during two additional 15-day public comment periods. The first comment period was held from March 18th to April 3rd. The proposed amendments were subsequently modified by DWR based on feedback received from OAL, prompting a second comment period held from August 23rd to September 9th.
First 15-day public comment period posted on 03/18/24
Modified text of proposed MWELO amendments
Notice of public availability of modified text
Second 15-day public comment posted on 08/23/24
Modified text of proposed MWELO amendments
Notice of public availability of modified text
Documents Relied Upon and Incorporated by Reference
Other:
On October 16, 2024, WUE presented the MWELO amendments to the California Water Commission, which approved them in accordance with Water Code Section 161 (Resolution Number 2024-04). The meeting materials presented to the Commission are available online here.
The Department of Water Resources (DWR) can provide the CIMIS ETo Zone Map in an accessible format upon request. To receive this document, please email DWRCIMISPublicContact@water.ca.gov.
Annual MWELO Reporting by Local Agencies:
Beginning with 2020 MWELO reports, DWR is using the WUEdata portal for submission of Local Agency annual MWELO Implementation reports. Setting Up Your WUEdata MWELO Reporting Account
WUEdata Portal
2015 - 2019 MWELO Report Assistance and Forms:
To submit 2015-2019 MWELO Reports to DWR, please email WELO@water.ca.gov and request the report forms.
MWELO References
