Water Treatment

Our highest priority is the safety and quality of the water we provide. Learn what’s in water, how we treat it, and how we protect our water all the way to your faucet.

What's in Water


As water travels through lakes, rivers, soils, rock and other features in the environment it takes with it characteristics of those environments.  Helix obtains water from three primary sources -- the Colorado River, the State Water Project and, locally, Lake Cuyamaca.  We manage the characteristics of each water source through our treatment process.

Water Treatment Process


Wide photo of water treatment

Photo: Helix's R.M. Levy Water Treatment Plant

Step 1: Coagulation and Flocculation
The organic material in untreated water have a negative electrical charge. Positively-charged chemicals called coagulants are added to the water to bind with the organic material and cause it to clump together. The clumps are called floc. 

Step 2: Sedimentation
When floc forms, it sinks to the bottom of the sedimentation basin. The clarified water, at the surface, flows to the next step in the treatment process.

Step 3: Disinfection With Ozone
Disinfection destroys or inactivates any organisms in the water. We use ozone as our primary disinfectant because it offers important advantages:

  • Ozone destroys or inactivates a wide range of organisms in water
  • Ozone needs little contact time with the water to be effective
  • Ozone produces fewer potentially harmful disinfection by-products than other disinfectants
  • Ozone removes most of the smell and taste issues people associate with tap water

We create the ozone by passing oxygen through high voltage generators. Oxygen(O2) molecules break and oxygen radicals(O1) bind to oxygen molecules and form ozone (O3). The ozone molecules bubble up through the water column and destroy or inactivate the organisms present.

Step 4: Filtration
Our filters consist of a layer of anthracite coal (charcoal) and a layer of sand. Filtration works through two basic processes, straining and adsorption. Straining removes material and particles that are too large to pass through the filter material. Adsorption works through similar properties as coagulation. Material and particles that can pass through the filter material adhere or stick to the surface area of the anthracite and sand material. This happens on a very small scale removing very fine material and particles. 

Step 5: Chloramination
The State of California’s water quality regulations require that we maintain a disinfectant in our water as it passes through the distribution system to protect against possible contamination. Chloramines are formed by combining chlorine and ammonia. Chloramines are more stable and provide a longer lasting disinfectant residual than chlorine alone to ensure the water is protected.

How We Protect Water Quality

Our chemist, biologist and treatment plant and distribution system operators assure that our water meets all standards set by the EPA and the State of California.

200 Tests per Day
We collect and analyze 200 water samples a day from multiple points throughout the water treatment process.

System Tests
We continuously test water samples from our distribution system to ensure water quality levels all the way to customer.

No Lead Pipe
We have no lead pipe or service laterals in our water distribution system.

Backflow Prevention
Backflow prevention devices prevent the flow of water from potentially contaminated sources back into our distribution system.

Flushing
Sediments can accumulate in the system over time and can be stirred up by velocity changes or main breaks — causing discolored water. And some areas of the system may experience longer retention times. Flushing is used to clear water from the system and maintain water quality.