East County AWP Program

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 several groups – Helix Water District, Padre Dam Municipal Water District, the City of El Cajon and the County of San Diego are producing a sustainable water supply for East County.

Video Transcript: The Clear Solution

water is essential to our everyday life
we must ensure a strong water future and
plan wisely
preserve the environment and recycle and
reuse this most precious resource
recycling and reusing the water we
already have is
most of our drinking water travels
hundreds of miles to get to us
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
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
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
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
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 levy water
treatment plant before being delivered
to customers
as safe clean drinking water
this program will provide east county
with about 30 percent of its drinking
it’s a smart investment that will
provide water at a competitive cost
compared to imported water
and help control wastewater treatment
east san diego county will join
communities around the world
already creating purified drinking water
using similar technologies
in london belgium singaporean 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
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

How It Will Work

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).

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. 

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.

Step 4: Treatment and 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 percent 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.

Benefits of East County AWP: Clean, local, drought-proof drinking water; supplies up to 30% of east county's drinking water; eliminates 15 million gallons/day of treated wastewater discharge into the ocean; offers a cost effective solution

Learn More

Virtual Tours

The East County Advanced Water Purification program offers multiple tour options. These include a 360-degree virtual reality video and online, staff-led tours.

Check tour availability here 


Explore the East County AWP

Explore the program’s website, where you will find videos, a story map, fact sheets, studies and more.

Explore Orange County's AWP

Orange County’s Groundwater Replenishment System provides drinking water for 850,000 people.

Explore San Diego's AWP

The Pure Water San Diego Program will go online in 2035 and provide one third of the city’s water supply.


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