What’s in Los Angeles’ Tap Water? Contaminants and Filtration

Los Angeles, the City of Angles, of sunshine, of culture, of creativity — but few moments are spent contemplating the water flowing through their faucets each morning. Supporting almost 4 million people, dependent upon the Los Angeles Department of Water and Power (LADWP), this gigantic water system supplies life and functionality to the region.

However, according to the Environmental Working Group (EWG), Los Angeles tap water contains 24 contaminants , with nine exceeding health-based guidelines. In this guide, we will look closely at the water quality in Los Angeles. We will talk about common contaminants and explain how the right filtration systems can give you fresher and healthier water at home.

The short reply is yes, but on conditions.

LADWP water supplies are within all the EPA and California State Water Resources Control Board -established federal and state regulations. These regulations stipulate the legal boundaries of most pollutants, including heavy metal elements, bacterial organisms, and chemical pollutants.

Still, “meeting legal limits” does not always equate to “safe.” Some experts and health groups contend the feds' style of safety thresholds are obsolete and fail to account for the latest long-term studies of long-term exposure to some pollutants.

That is, Los Angeles drinking water is technically legal — but all bets are off regarding long-term health.

Few capitals of the globe depend upon so extensive and sophisticated a system of bringing-in water as Los Angeles. Due to the area's inherent dryness, much of the water it uses comes by importation, as it does, from the rest of California and adjacent states.

Primary sources of the City are:

• The Los Angeles Aqueduct, conveying snow-melt through the Sierra Nevada.
• The Silver King Mine, dug by the Little Joe Mine Company.
• State Water Project, to carry water from Northern to Southern California.
• Local groundwater, giving feed to the principal supply.

Once the water gets there, it’s treated, disinfected, and pumped through the 7,000+ miles of pipeline. Along the pipeline, the water potentially collects trace contaminants from natural earth deposits, farmland runoffs, or aged plumbing materials.

Even treated water may have trace amounts of chemicals, metals, and minerals. Some are naturally occurring, and others are the result of human action like farming, manufacturing, or garbage dumping.

In Los Angeles, most of the prominent pollutants typically lie within the following categories:

• Heavy metals – such as lead, copper, and chromium.
• Agricultural chemicals – nitrate and pesticide residues.
• Disinfection byproducts – developed once chlorine combines with organic material.
• Radioactive substances – e.g., uranium and radium of rock strata.

Lead, arsenic, and chromium-6 are among the most talked-about heavy metals in the water of California.

Lead doesn’t typically emanate from the source of the water. However, it seeps through pre-existing service lines and home plumbing lines, which were installed prior to current pipeline regulations . Exposure, even through low-degree means, has effects on the brain growth of children and long-duration behavioral and learning difficulties.

Arsenic naturally exists within the earth’s crust and may dissolve within groundwater. Long exposure has effects related to higher risks of skin, bladder, and lung cancers.

Chromium-6, or hexavalent chromium, is an industrial chemical that can contaminate water supplies as a result of metal plating or manufacturing byproducts. Studies have indicated that chronic exposure tends to increase the incidence of some cancers.

While the Los Angeles concentrations of these contaminants are typically lower than federal protections, minimizing exposure to the extent possible is prudent — particularly among susceptible populations of pregnant females, new-borns, and elderly people.

Click here to learn more about Expert Insight: 5 Surprising Contaminants Found in Your Tap Water: How to Remove Them.

Los Angeles might be the city, but much of the water Los Angeles imports goes through agricultural areas where fertilizers abound. These fertilizers deposit nitrates, and nitrates are not removed by treatment.

Nitrates are of special concern for babies, because they have the ability to disrupt the oxygen-carrying ability of the blood and cause “ blue baby syndrome .” Chronic nitrate exposure in adults has become associated with significantly higher odds of thyroid disease and some cancers.

To disinfect water, LADWP employs the use of chlorine and chloramine to eliminate the presence of bacteria and viruses. These disinfectants, though, react with the organic material — including dead plants or crop residue — and become disinfection byproducts, trihalomethanes (THMs) , and haloacetic acids (HAAs) .

Although the chlorination system has proved to be among the most significant public health accomplishments ever, certain investigations have associated elevated concentrations of DBPs with the reproductive disorders, liver injuries, and heightened cancer hazard.

Some areas of Southern California have naturally occurring uranium and radium present in rocks beneath the surface. These may be present in trace amounts and are absorbed by the water as it flows through these rocks.

These particles are not harmful immediately, but steady exposure long term has the ability to destroy the kidneys and cause the risk of cancer.

Even where the water is properly drinkable, certain residents complain of an unpleasant chlorine flavor or muddy smell. This occurs where disinfectants linger behind the treatment of the water or where there are present natural organics.

High levels of minerals, or hard water, may also give off the flavor of chalk and cause white spots to form on fixtures and appliances. Hard water, though nontoxic, may impact the efficiency of the plumbing and the longevity of appliances that use water.

According to National Sanitation Foundation , installing NSF-certified filtration systems and regularly replacing filter cartridges can improve tap water quality.

Activated carbon filtering is the most popular household type. It can reduce bad smells. Nevertheless, a carbon filter does nothing for nitrates, heavy metals, or radioactive contaminants.

For broader shielding, the best are the reverse osmosis, or RO, systems. They involve the application of stages of filtering, including pre-filters of sediment and activated carbon, and then semi-permeable membrane, which prevents contaminants, such as microplastics and PFAS, at the molecular level.

Reverse osmosis systems are recommended for comprehensive filtration, effectively removing contaminants like heavy metals and disinfection byproducts. Waterdrop RO system provides a sophisticated multi-step filtration process with tankless design, delivering fresh, clean water immediately without occupying too much space.

Pitcher filters are cheap and convenient, but they only perform well by the brand and type. Some, such as the Waterdrop Chubby pitcher , contain several layers of activated carbon, and they are capable of removing chlorine and flavor problems.

Though they don’t have full-spectrum filtration like the RO systems , they are best suited for renters or people seeking the initial step of ease.

Each home's water quality may differ due to the area, pipes, and aging of the structure. To learn what is in your water:

• Residents can access the LADWP's annual Drinking Water Quality Report online to review contaminant levels and compare them with health-based guidelines.
• Use a home water test kit — found at most hardware stores or via the internet.
• Check the EWG Tap Water Database — put in your ZIP code and view test data for your region.

While Los Angeles tap water meets federal standards, residents may consider additional filtration for enhanced safety. Trace amounts of pollutants won't immediately kill you, but reducing long-term exposure can help promote better health, particularly among households and young people. It is an easy, affordable means of ensuring peace of mind and better everyday hydration by making use of a trustworthy water filtration system.

By learning where the water comes from, identifying where the pollutants are, and investing in good filtration, you are able to have water that’s refreshing and safe — straight from the kitchen faucet.