East County Advanced Water Purification (AWP)

AWP stands for advanced water purification. It's a treatment process to turn recycled water into drinking water. 

The East County AWP is a partnership between Helix Water District, Padre Dam Municipal Water District, the City of El Cajon, and the County of San Diego to produce a sustainable water supply for East County.

Video: East County Advanced Water Purification Program

  1. Video Transcript: The Clear Solution

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]

How It Will Work

Sprinkler Head

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 the 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, advanced oxidation, and disinfection. They will produce water so pure that we must add helpful minerals back into the water before we distribute it.

Lake Jennings

Step 3: Detention
Padre Dam will transport the purified water through an 11-mile pipeline to Lake Jennings. There the water will be stored 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.

Levy Water Treatment Plant

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.

When it Will Start

The participating agencies held a groundbreaking ceremony on June 1, 2022, to launch construction. There are three design and construction "packages" to fund and complete. A fourth package focuses on water treatment byproducts. 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 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.

Package 4
The East County AWP and the City of San Diego will determine how to dispose of brine and other byproducts of the advanced treatment process.