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Casitas Water Security


Even with our drought and current lake level, Casitas has water resources for the future. The District is actively engaged in managing existing local water resources and planning for water security.   Our current water supplies and Urban Water Management Plan are summarized below.

Our Current Water Supply 

Casitas Municipal Water District's water supply is comprised of water stored in Lake Casitas and groundwater in the Ojai Valley. 

5-year average water sources Current Water Supply

Historical water by use is shown in the chart below. While water use fluctuates from year to year based on weather and outdoor water demands, there has been a clear reduction in customer water use in response to the current drought (post-2013) and previous drought (post-1989).

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Casitas manages water supply primarily through the Water Efficiency and Allocation Program, or WEAP. The WEAP ensures allocations of water and conservation targets are in line with drought conditions. 

Read the full WEAP Report here.


In accordance with the WEAP, the District updates its supply projections and drought stages at the end of the rainy season, which is typically in April each year.

Read most recent annual water supply assessment.

The updated five-year supply planning outlook indicates that the District's current water demands can be met through the next  5+ years, using a combination of water from Lake Casitas and groundwater. This is based on a conservative assumption that with the given demand rates, 2013 evaporation, with no additional rainfall and runoff, Lake Casitas would reach Stage 2 levels in 26 to 30 months, and Stage 3 levels in 42 to 48 months.

Given the conditions noted above, the figure below illustrates that Lake Casitas could decline to approximately a 150,000 Acre-Foot capacity by December of 2023.


The figure below presents the annual high-low water storage fluctuations that Lake Casitas has experienced since 1970.  Lake Casitas storage was last at full storage capacity in May 2006 and has since been in a declining storage trend due to drought conditions, evaporation, environmental conditions, and water use. This year has shown a sharp reversal of that trend.

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Current Conservation Levels 

CMWD customers overall are doing an excellent job conserving at 66%.

April 2024 Conservation" at 66%.
Supply and Demand Study 

In April 2021, the Casitas Board of Directors adopted updated long-term planned demands and operational yield for existing supplies, which are reflected in the 2020 Urban Water Management Plan. This study provides a summary of the future long-term demand analysis, future long-term supply analysis, and long-term supply and demand scenarios that were evaluated and adopted. 

CMWD 2021 Lake Casitas Water Supply and Demand Study


Planning for the Future:  Urban Water Management Plan 

As our community's water experts and responsible stewards of our water resources, Casitas is constantly working to plan for a more sustainable and reliable water future. This process involves taking a comprehensive look at our available water supplies and the water needs of our customers, and how we can ensure there will be enough water to go around, both now and into the future.

Every five years, the District prepares an Urban Water Management Plan - a state-mandated planning document to assess long-term water supplies and demands. The plan outlines:

  • The reliability of water sources over a 20-year timeframe
  • Demand management measures and water shortage contingency plans
  • Progress toward meeting targeted reduction goals for per-person water consumption

Casitas' adopted Final UWMP is available here:

 2020 Urban Water Management Plan - FINAL


White Paper on Supply Options 

The Ventura River Watershed has been experiencing extreme dry conditions that have persisted since 2012. While Lake Casitas is designed to supply water during multi-year drought conditions, lake levels as of September 2022 are approximately 31 percent of capacity (73,600 Acre-feet remaining). Should dry conditions persist, the Casitas Board of Directors will face major decisions in the near term related to drought response and planning. The purpose of this white paper is to summarize information currently available on management options.

White Paper on Short List of Supply Options for Drought and Emergency Preparedness



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