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Is San Diego Tap Water Safe to Drink?

Scott Winfield
Last Updated on
by Scott Winfield

If you live in San Diego or are just visiting, you might wonder whether the city’s tap water is safe to drink.

Yes, san diego tap water is safe to drink. However, we strongly recommend you to use a water filter due to the city’s poor water safety record.

San Diego Water Quality Report: What is in the Water?

The city of San Diego has a spotty record on water safety, although it has made great strides in recent years. As recently as a few years ago, San Diego was ranked to have some of the worst tap water in the country. As the nation’s eighth-largest city, San Diego’s water quality rankings were a major black eye.

One problem was the quality of the water coming into the system. Most of the issues, however, were due to infrastructure.

Water main breaks, contamination from older pipes, chemicals leaching into the system, etc., have all plagued the water system in the past. Since then, San Diego has made a concerted effort to address the outstanding issues.

The city has updated piping and replaced pipes that had lead in them or were over a hundred years old. It also updated its water mains, which decreased the number of ruptures the city experiences annually.

In January 2020, San Diego announced a major, city-wide initiative to use drones to inspect pipes and replace all old pipes by 2024.

Concerning the current status of water in San Diego, its quality exceeds EPA standards, meaning it is, in the eyes of the EPA, legally compliant with the Safe Drinking Water Act.

San Diego Water Contaminants

As of the last report, San Diego has several contaminants in its water. Over the years, ten contaminants have been tested to exceed federal levels of safety:

  • Bromodichloromethane
  • Bromoform
  • Chloroform
  • Chromium (hexavalent)
  • Dibromochloromethane
  • Dichloroacetic acid
  • Radiological contaminants
  • Total trihalomethanes (TTHMs)
  • Trichloroacetic acid

Is The Water Hard or Soft?

San Diego water is considered very hard, with over 180 PPM of minerals in a water sample. This puts it in the highest grade for water hardness.

Where San Diego Gets its Water From

San Diego gets most of its water from the San Diego County Water Authority. The San Diego County Water Authority gets its water from the Colorado River and the State Water Project. The water provided through those sources is raw water.

A lake

Both water sources are subject to drought, geology, and land activities. San Diego monitors both sources and adjusts its ratio from each accordingly. By doing this, the city can ensure the drinking water will be safe once treated in the San Diego Water Treatment plant.

The city also gets less than 10% of its water from treated sources. The treatment plants include the Skinner Water Treatment Plant, Twin Oaks Valley Water Treatment Plant, and the Carlsbad Desalination Plant.

How Tap Water Is Treated in San Diego

The city’s Public Utilities Department takes a tiered approach to treating water that enters the San Diego water treatment plant:

Watershed Protection

San Diego closely monitors any sources of water or water storage points. The monitoring includes strictly enforcing swimming, boating, and dumping regulations.


Chemical components get mixed into the water entering the water treatment plant. Many particles are negatively charged, causing them to repel each other. Coagulation changes the particles from negative to neutral.


Coagulated water gets mixed and makes neutral particles in the water collide. These particles clump upon impact, creating what is called “floc.”


Once mixed, the water flows through sedimentation basins. Because the floc is heavier than the water, it drops into the basins, taking particles of contaminants with it. Clear water gets skimmed off the top of the sedimentation basins.

Primary Disinfection

The collected water is then disinfected. The method depends on the plant the water flows through on its way to the tap water system.

The Alvarado and Miramar water treatment facilities use ozone to disinfect water. The Otay facility uses chlorine dioxide. Both processes disinfect the water and improve its taste.


After disinfection, the water flows through deep filtration beds. Even the smallest contaminant particles get picked up as the water works through the beds. The result is very clean water.

Secondary Disinfection

Chlorine and ammonia get added to the water after the filtration process. The added chemicals merging produces chloramines, which fight microbial contamination. Water is also adjusted accordingly to maintain a healthy pH level.

The result of going through that process is highly clean, highly drinkable water that gets distributed throughout the San Diego area.

Do They Have the Cleanest Tap Water?

The best answer is “No, but they are working very hard to improve their already safe water.” San Diego had and has a lot to overcome because of an aging water system.

It has made great strides through infrastructure improvements to improve its water quality. While it still is not the greatest, it is improving with each update to the water treatment system.

Final Thoughts

San Diego’s water has had issues in the past, but the city is working hard to improve the water’s overall quality. The city’s robust water treatment plant helps ensure the entire water system stays clean.

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Scott Winfield
Scott Winfield
My name is Scott Winfield and researching and writing about water filters and other strategies to purify water has become my full time passion in recent years. I'm glad that you found our site and you can look forward to authoritative and well researched content here to help you get the best in water.
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