Current Water Levels and Water Quality

Water Storage and Use

California Department of Water Resources


The Project starts at Lake Oroville in Northern California and continues to Lake Perris in Southern California. When it reaches Lake Perris, the SWP joins in with the Metropolitan Water District system to supply water to Southern California.

State Water Project water travels through the Sacramento-San Joaquin Bay Delta (Delta) before making its way to Southern California. The Delta has experienced water quality, environmental and legislative challenges over recent years, making it important to continue to look for ways to find local water supply sources.

Lake Perris is a multi- purpose reservoir providing: 1) water supply; 2) recreation; 3) fishery and wildlife enhancement; 4) emergency storage for water deliveries; and 5) incidental flood protectionWithout warning, the Department of Water Resources may raise or lower water elevations to meet the water demands of Southern Califronia residents.  Anytime the lake elevation is impacted it may have negative impacts to recreation.  CA State Parks has no control of these desicions.   When boating always be on the look out within the 5 mph areas for submerged rocks and trees.  

To view the current lake elevation visit DWR water elevation report


Harmful Algae:

Current Status:   For the most current information on the water quality at Lake Perris please visit:  Latest Harmful Algae Report for Lakes (Please scroll down to Riverside County when usingthe link to find Lake Perris. 

Lake Perris undergoes water testing to ensure visitor safety.  

California’s lakes, rivers, and streams are a great place to cool down as the temperature heats up this summer. But as the warmer weather approaches, so does the start of algal bloom season on the state’s waterways.  

DWR urges swimmers and boaters to take the necessary precautions and stay away from algae. While some algae are harmless, certain types can produce toxins that can make people and animals sick. There is no way to tell if an algal bloom is toxic just by looking at it.

DWR regularly tests the State Water Project (SWP) water for algal toxins. When tests are positive, signs are posted on site, at the reservoir, and online. Once toxic algae are found, testing continues, and algae levels/warnings are not reduced until lab results show the water has been below the positive test level for two weeks.

There are multiple factors that can cause algae to grow, such as warm water temperature, calm conditions, and certain nutrients in the water. Blue-green algae (cyanobacteria) naturally occurs in lakes and can grow very rapidly to become an algal bloom.

For more information about harmful algae blooms please visit CA Water Quality Information