East County Advanced Water Purification

The East County Advanced Water Purification Program will create a new, local, sustainable and drought-proof water supply. The program will use state-of-the-art technology to purify East San Diego County’s recycled water to produce up to 30% of East County’s drinking water supply.  It's a partnership between Helix Water District, Padre Dam Municipal Water District, the City of El Cajon, and the County of San Diego.

Construction Updates

Construction is underway and you can follow the progress. There are five design and construction "packages". East County AWP is expected to go online in 2026. 

Package 1
Design and construction of a new water recycling facility, advanced water purification facility, solids handling facility, product water pump station, and a new visitor's center.

Package 2
Design and construction of the purified water pipeline to Lake Jennings, a dechlorination facility and an inlet, where the dechlorinated water will flow into the lake.

Package 3
Design and construction of pump station expansions and improvements and wastewater and residual pipelines. Each segment is 3 miles long.

Package 4
Design and construction to rehabilitate the existing East Mission Gorge Force Main and a new East County Residuals Line. This package is a collaboration between the East County AWP JPA and City of San Diego. 

Package 5
Design and construction of an energy recovery system to produce 3 megawatts of renewable energy. Construction is anticipated to begin in 2026 and be completed in 2028.


Step 1: Recycled Water
Padre Dam Municipal Water District has been producing recycled water for irrigation and Santee Lakes for over 60 years. To provide recycled water for the East County AWP Program, Padre Dam will begin recycling wastewater from the City of El Cajon and County of San Diego (Lakeside, Winter Gardens, and Alpine).

Advanced Treatment Steps

Step 2: Advanced Treatment
The recycled water produced in step one will go through a four-step advanced treatment process. These steps are membrane filtration, reverse osmosis, UV/advanced oxidation, and free chlorine disinfection. This advanced water purification treatment process creates water so clean, it's near distilled in quality and helpful minerals must be added back into the water before it goes to the next step. 

Step 3: Detention
The purified water will be transferred through a 10-mile pipeline to Lake Jennings. There the purified water will be added to the lake with water from the Colorado River and Lake Cuyamaca. According to regulations, the water must be stored in a lake or aquifer before it is distributed to customers.

Step 4: Treatment & Distribution
Helix treats the water in Lake Jennings at the district's R.M. Levy Water Treatment Plant. It's then distributed to homes and businesses in the cities of La Mesa, Lemon Grove, and El Cajon, the Spring Valley community, and unincorporated areas of the county. The purified water from the East County AWP will provide up to 30% of Helix's water supply.

Video: East County Advanced Water Purification Program

Water is essential to our everyday life. We must ensure a strong water future and plan wisely to preserve the environment and recycle and reuse this most precious resource. Recycling and reusing the water we already have is vital. [Music] Most of our drinking water travels hundreds of miles to get to us. [Music] We need a local sustainable water supply to secure a reliable water future that will guard against drought, protect the environment, enable us to have a locally controlled source of water and economize costs. [Music] The East County Advanced Water Purification program provides a strong water future for communities in East San Diego county. Using state-of-the-art technology to purify recycled water, it will create clean, safe, high-quality drinking water. The program is a collaborative effort with Padre Dam Municipal Water District, county of San Diego, city of El Cajon and Helix Water District. [Music] 

Here's how it works. After water goes down the drain, it will be treated at a water recycling facility. Then the recycled water will go to the advanced water purification facility. Here, the purification process begins with membrane filtration. With filters resembling straws, water is forced through microscopic holes. This process filters out particles 300 times smaller than a human hair. Next, water is pushed through reverse osmosis membranes that remove particles 100,000 times smaller than a human hair. Pharmaceuticals, chemicals and pathogens are removed, resulting in water that is near distilled quality. Then, the advanced oxidation process uses chlorine with ultraviolet light to break down remaining organic molecules. Similar technology is often used to sterilize surgical instruments. The water is now so pure, minerals are added back in for taste and to ensure a proper and healthy pH level in the water. The next step is free chlorine disinfection. Here, chlorine is mixed with the purified water to ensure the water meets high state and federal drinking water standards. The purified water will then be delivered to Lake Jennings, a reservoir in East County. To protect fish and plant life in the reservoir, the water is first dechlorinated and then combined with local and imported water. Finally, it's treated once more at the R.M. Levy Water Treatment Plant before being delivered to customers as safe, clean, drinking water. 

This program will provide East County with about 30% of its drinking water. It's a smart investment that will provide water at a competitive cost compared to imported water and help control wastewater treatment costs. East San Diego County will join communities around the world already creating purified drinking water using similar technologies in London, Belgium, Singapore and California. In fact, Orange County is home to the largest advanced purified water facility in the world. For more than a decade, this facility has delivered advanced purified water to homes and businesses, including some popular amusement parks. [Music] The Advanced Water Purification program will ensure a safe, reliable, drought-proof, locally controlled and environmentally sound water supply. East County Advanced Water Purification for a strong water future. It is the clear solution. [Music]