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​The groundwater and raw surface water that enters our system isn't ready yet to drink. To make it safe for drinking, we must filter the surface water, disinfect and test it to confirm that it's ready for your family.

To accomplish that process for millions of gallons of water every day, we use a variety of high-tech systems, including treatment plants that can filter at microscopic levels, remove and neutralize any contaminants, and pump heavy water up and to the network of pipes that reaches your home.

Depending on the source of your water β€” groundwater or surface water β€” there might be contaminants or other material that needs to be removed and disinfected.

Groundwater has been naturally filtered by the earth, but could contain impurities because of the erosion of natural mineral deposits. Anything that's in the earth may over time make its way into the water. Similarly, surface water that comes from canals also could include other material that's washed down from mountains and streams. It's our job to filter out what shouldn't be there, and deliver only what should: clean water.


Depending on the plant, we use different technologies to filter surface water. Our Anthem plant uses a high-tech membrane system that filters water through thousands of membrane filters β€” they look like pieces of spaghetti. Water molecules are large enough to pass through the membrane, but contaminants cannot.

At other plants, we use a system called dissolved air flotation (DAF), in which bubbles are injected into the raw water to propel contaminants upward to the surface. Then the water is skimmed to remove contaminants. After DAF, the water is filtered again. This is a process we use at our White Tanks facility.

After filtering the water, we test it for clarity. When it's ready, the water moves on for disinfection.


The water at this stage has been filtered, but could contain microorganisms that need to be neutralized. Typically, we use sodium hypochlorite, an industry standard, to kill the bacteria.

Throughout the process, and after we've finished treatment, we test and monitor the water to ensure it meets all state and EPA water quality standards.