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Is San Francisco Tap Water Safe to Drink?

Scott Winfield
Last Updated on
by Scott Winfield

When you reach for a glass of water from your faucet, you might hesitate and consider if water from the tap is safe to drink.

In San Francisco, there are still plenty of other questions you should be asking about your water. Just because it’s safe to drink doesn’t mean it’s the highest quality.

San Francisco Water Quality Report: What Is in the Water?

The San Francisco Public Utilities Commission manages San Francisco’s tap water supply. This organization regularly releases water quality reports for the public to learn more about their water.

According to the 2021 water quality report, the organization conducted over 90,000 water tests in the year. This data gives a comprehensive view of the particles in the water.

Some contaminants found in water are leftovers from the purification process, while others are from the environment. According to an EPA report, there were no contamination levels high enough to count as a violation.

Still, it’s good to know what’s in your water. Here’s a brief list of some of the contaminants found in San Francisco’s tap water:

  • Trihalomethanes
  • Five Haloacetic Acids
  • Bromate
  • Organic Carbon
  • Chloramine (as chlorine)
  • Fluoride
  • Chloride
  • Sulfate
  • Copper
  • Lead
  • Calcium
  • Magnesium
  • Phosphate
  • Potassium
  • Silica
  • Sodium

While this information may seem surprising, it’s essential to understand that many of these contaminants were in low concentrations. The EPA regulates that small amounts of copper and lead in tap water, for example, are acceptable.

Is The Water Hard or Soft?

Water hardness refers to how many minerals are in the water, with the higher levels being harder water. When considering if San Francisco’s tap water is safe, it’s not necessarily about whether the water is hard or soft. Most of this can be about preference.

Generally, San Francisco’s water is soft. If you’re curious about your water, there are signs around the house to indicate your water’s hardness.

Hard water will leave behind a film on dishes, or you may notice a crusty white build-up on faucets. These are both results of mineral build-up.

Other hard water signs include difficulty cleaning bathtubs or showers and soap that won’t foam.

You can quickly test the water by filling a clear bottle with tap water, adding dish soap, and shaking the bottle. If the shaken bottle has plenty of bubbles and clear water, the water is soft, but if the bottle doesn’t have bubbles and has cloudy water, it’s hard.

Where San Francisco Gets its Water From

Most of the tap water in San Francisco comes from the Tuolumne River. This river supplies the Hetch Hetchy Regional Water Reservoir, which single-handedly gives water to 2.4 million people around California.

Tuolumne River
Tuolumne River, California

Otherwise, San Francisco’s water also comes from surface water reservoirs in the Sierra Nevada, Alameda County, and San Mateo County. Surface water is simply another term for bodies of water above ground, so any nearby lakes or streams may be a part of this.

Some water comes from groundwater sources, naturally occurring water below ground. This water is in San Francisco and San Mateo aquifers.

It’s crucial for California water supplies to come from multiple sources, especially since things like rain and melting snow are rare events to resupply the reserves.

How Tap Water is Treated in San Francisco

San Francisco’s tap water is treated in multiple ways. For the most part, the process is simple, and it includes a mix of adding chemicals or treating the water with UV light.

UV Lights
UV Light System

The Hetch Hetchy water reservoir is one of the few water sources in America that don’t require treatment according to federal regulations. Despite that, there are still some minor treatments to the water from this source.

The water undergoes disinfection from UV light and chlorine. Like many other cities, San Francisco adds some fluoride for dental protection. Finally, chloramination is a final disinfection process that keeps the water safe for longer.

Water from other sources undergoes a more extreme treatment process, following federal regulations. This water has to go through filtration, disinfection, taste and odor control, fluoridation, and corrosion control.

Water treatment is an essential step in keeping San Francisco’s tap water safe to drink, and despite the chemicals, it is a secure process.

Do They Have the Cleanest Tap Water?

San Francisco’s tap water is clean, and they can feel proud of having one of the only water source in America that don’t require treatment. The fact that they still treat that water should show how clean it is. Plus, the San Francisco area has had no recent violations in water quality.

However, whether it’s the cleanest in the United States is up for debate. It’s hard to say who has the purest water, and it will rely partially on personal preferences.

There is an annual Berkeley Springs International Water Tasting contest, but San Francisco hasn’t won. Some may be proud to know that other local California cities have taken the title in Santa Barbara and the Metropolitan Water District of Southern California. So perhaps the cleanest water isn’t too far away.

Final Thoughts

San Francisco’s tap water is safe to drink, and while it may not have won any awards, it undoubtedly hasn’t violated any safety regulations. San Francisco can pride itself in knowing it’s water source is one of the purest sources in America.

While some facts about water safety and purification may seem surprising, you can be rest assured that your water has undergone standard practices known to be acceptable for health.

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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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