Science

How to best filter your L.A. tap water based on your ZIP Code

Published

2 years ago

July 22, 2024

How to best filter your L.A. tap water based on your ZIP Code

Nearly a year ago, I scribbled “Replace Brita filter” on my to-do list. But the errand perpetually fell by the wayside. There were so many more pressing tasks to complete.

“Oh, it’s fine,” I thought. “How bad can it be?”

Let’s just say that a day into reporting this story, I ran out to the market and bought a three-pack.

We reach for our water taps more than almost any other object in our homes — to brush our teeth, wash our faces, make coffee or tea in the morning. To cook meals, rinse dishes and wipe countertops. To water the plants, do laundry and fill our pets’ bowls. To shower and shave. And most often for a drink.

In L.A., water rules everything around us. Drink up, cool off and dive into our stories about hydrating and recreating in the city.

But how much do you really know about what’s in your tap water? And if you filter it, are you using the right technology? Many of us may not be fully aware of where our water even comes from.

That’s because the water that flows into our homes in the L.A. area can be surprisingly different, ZIP Code to ZIP Code. The level of arsenic found in Compton’s tap water may differ wildly from that found in Glendale. Malibu’s tap water may have more hexavalent chromium while Pasadena’s doesn’t have any. One tap does not fit all.

“Where you are, the location, it really makes a difference in your water quality,” said Tasha Stoiber, a senior scientist at the Environmental Working Group, a nonprofit research and advocacy group focusing on environmental health.

We went to the source, so to speak — experts in the realms of science, academia and water filtration — to help you navigate the often complicated, ever-fluid world of residential tap water, so that you can make smarter and more informed choices about how to purify your H20.

L.A.’s water sources

Like most major cities, the Greater Los Angeles area is served by a dizzying number of community water systems. In California, there are 2,913 of them to serve about 39.025 million people — and those are just the larger ones that operate year-round, according to the EWG’s Tap Water Database.

Each utility company treats the water in its assigned municipality differently before it flows through consumers’ faucets. That’s because each draws from different water sources. One area’s tap may be coming from rivers and lakes (otherwise categorized as “surface water”) while another’s could be pumped from wells from beneath layers of rock and sediment (categorized as “groundwater”).

Depending on where the water travels, it may pick up different undesirable contaminants. Surface water, for example, could have runoff that includes nitrate used to fertilize land in agricultural areas. Groundwater could have naturally occurring chemical elements, such as arsenic, that come from bedrock.

More often than not, L.A. area tap water comes from a mix of these sources. Our utility companies draw from different aqueducts, those large, often concrete ditches or canals that extend from the source to the water treatment plant. From there it flows through pipes, underground, to your home.

In 2023, the Los Angeles Department of Water and Power — which serves about 4 million people throughout the city of Los Angeles — sourced its tap water from the Los Angeles Aqueduct, the California Aqueduct and the Colorado River Aqueduct as well as from local groundwater, according to its most recent drinking water quality report.

The specific geographic location of a water source also determines what ends up in your tap water. A lake near a highly industrial area risks containing more pollutants than water coming from a lake in the High Sierras.

Another reason the water might be different between ZIP Codes: Utility companies have different resources at their disposal.

“The size of the drinking water system can be an indicator of the drinking water quality,” Stoiber said. “It’s based on economy of scale. The larger ones have more resources for treatment. Smaller systems can be at a bit more of an economic disadvantage.”

Federal and state water protections

There are federal regulations that require utility companies to stay below maximum contaminant levels for more than 90 pollutants in drinking water. They’re also required to publish an annual consumer confidence report with information about contaminant levels and water sources.

“But many of our drinking water regulations were set in the ’70s and ’80 and are not as protective as they should be,” Stoiber said. “There are contaminants in your drinking water that don’t have regulations around them.”

How harmful these contaminants are, and how much you’d have to ingest over time to affect your health, is contested. But in general, however many pollutants you might find in L.A.’s tap water, there are not enough to make you seriously ill in one gulp.

Some good news: In April, the U.S. Environmental Protection Agency finalized new regulations around a family of about 15,000 chemicals known as PFAS. They’re often referred to as the “forever chemicals” because they don’t break down in the environment. California also voted in April to finalize a limit for hexavalent chromium, or “Chrome 6,” which many people know as the carcinogenic chemical that the Pacific Gas and Electric Co. contaminated residents’ groundwater with, from 1952 to 1966, in Hinkley, Calif. — the legal upshot of which was depicted in the film “Erin Brockovich.” But those changes won’t be immediate.

“Upgrading water treatment plants is expensive and takes years,” said USC’s Daniel McCurry, who researches water supply and treatment. “Most smaller utilities, especially, just won’t have the money to make the upgrades in the initial time frame.”

2027, McCurry notes, is the deadline for utilities to complete their “initial monitoring” before the new regulations for PFAS go into effect in 2029.

Photo illustration of a hose faucet on a blue background pouring water on the right, with dirt, grass and rocks on the left.

How to determine your water quality

So where to start? It’s easier than it might seem. First, search for your consumer confidence report on your utility company’s website. You can then cross-reference that information with EWG’s free Tap Water Database, which allows you to type in your ZIP Code (look for the prompt “Is your water safe?”). It then will populate your water utility company and the number of people it serves. From there, you can click on “View Utility” to produce an easy-to-decipher report listing the source of your water and contaminants detected in it.

When I typed my own Silver Lake ZIP Code in for a water quality analysis, the results did not put me at ease. It listed nine contaminants detected in my water, among them bromate and uranium. Some of these were found at levels that far exceeded the standards of the EWG but were still below the legal limit.

I called the LADWP to make sense of what I’ve found.

“There’s no health concern,” LADWP’s director of water quality, Jonathan Leung, said of my findings, stressing that the contaminants were far below the federally mandated legal limit. “That’s where, collectively, all the toxicologists and water quality specialists and scientists have worked together to set national standards. As a water quality utility, that’s what we set our sights on. The public should take confidence that the legal limits are protective of public health — and we strive to do better than that.”

McCurry added that the EWG and EPA have different standards for the amount of contaminants found in water.

“When the EPA sets a water contaminant limit, it’s a balance between protecting public health while staying realistic about the treatment technology we have and how much it costs,” McCurry said. “Everyone’s perception or tolerance of risk is different, but for me, personally, I drink water straight from the tap and don’t worry about it. It’s very unlikely you’ll get sick from tap water, assuming the tap water meets federal regulations.”

How to test your water at home

Whatever your personal tolerance level, you can improve both the quality and taste of your tap water by choosing the right filter, experts say.

But, given the array of filtration products and techniques on the market, that’s easier said than done. Choosing from options like “ion-exchange demineralization,” “ultraviolet sterilization” and “chemical feed pumps” can be intimidating.

Take a breath. Then step back. Filtering should be a tailored approach, said Brian Campbell, founder of Water Filter Guru, which lab-tests and reports on residential water treatment methods and products.

“There’s no such thing as a one-size-fits-all water treatment solution,” Campbell said.

He added that even after reading utility consumer reports and nonprofit chemical analyses, you still may need to know more.

“[Those reports] will give you a general sense but not the whole picture, Campbell said. “Because water can be recontaminated after it leaves the treatment plant — like if your home has old plumbing with lead piping. But it’s a start.”

You can test your home’s water quality yourself using fairly affordable water test strips, available for about $15 in stores such as Home Depot. These, Campbell said, will “give you an indication of a handful of the most common 12 to 15 contaminants like lead, arsenic, chromium, nitrate possibly.” However it will only give you a range of those aforementioned contaminants, not the exact concentration in your water.

If you want specific information about the chemical levels, you can run a more in-depth test. The best way to do that, Campbell said, is through a certified lab, where the cost ranges from roughly $100 to more than $1,000 depending on how comprehensive you want to get.

How to choose a filter

Once you know what’s in your water, you’ll be able to choose the right filter technology to treat it, Campbell said. Here’s what he suggests using for some of the most common issues.

PFAS. This is the family of about 15,000 chemicals used for their water repellent and oil repellent properties, such as in nonstick pans or fast food packaging. “The most studied filtration method for this is activated carbon adsorption,” Campbell said. “It’s the most common technology used in pitcher filtration. Even the most simple water pitcher filters should theoretically reduce PFAS.” Reverse osmosis filtration systems also will address PFAS — it’s one of the most thorough techniques and includes activated carbon as one of its stages. Historically, these pricy systems were installed directly into sink pipes, but countertop versions now are available for renters.

Microplastics. “They get into the environment and break down into smaller and smaller pieces — so small you’d need a microscope to see them,” Campbell said. The best technique to address those — because they are suspended particles, floating in the water and not dissolved — is mechanical filtration, he said. The technology removes suspended particles, like pipe rust or sand and grit coming from a hot water heater. Reverse osmosis also would work. Distillation would be effective as well and is, per Campbell, one of the best to get rid of nearly all common contaminants. But, Campbell warned, “It requires a massive amount of energy and time to treat and distill a relatively small volume of water — so not the most practical.”

Disinfection byproducts. This is a group of chemicals created when common water disinfectants — typically chlorine — interact with organic matter (such as dirt or rust) that’s already present in the pipes that run from the distribution plant to your home or office, Campbell said. “Activated carbon adsorption is the best way to deal with this. Reverse osmosis will also deal with them because a component of that [technique] is activated carbon.”

Pesticides, herbicides and fertilizer. “This is more of an issue in agricultural areas,” Campbell said. Typically, he added, they can be treated using activated carbon and reverse osmosis.

Fluoride. Tap water is fluoridated in many areas because of its dental health benefits. But recent research suggests that prenatal exposure to fluoride may be linked to increased risk of neurobehavioral problems in children at age 3. “Reverse osmosis would be the best treatment for this, but there are a few adsorption media that can reduce fluoride, like a filter using bone char carbon (activated carbon that comes from animal bones) or a filter using activated alumina media, another adsorption media,” said Campbell.

Heavy metals. Lead is obviously the most infamous heavy metal water contaminant, but consumers also should watch out for arsenic (primarily from groundwater) and chromium 6 (which comes from industrial manufacturing). “Typically, for metals, reverse osmosis is the best option,” said Campbell. “Activated carbon works for chromium 6 but not for arsenic. Distillation, again, gets rid of everything but it’s not practical.”

Hard water. Hard water is caused by mineral buildup, which isn’t bad for your health but can create limescale on appliances like your water heater. It also can affect your beauty routine. “Soap doesn’t lather as well with hard water,” said Campbell. “Your hair might feel brittle and it can irritate skin issues like eczema.” He recommends treating the issue at the water point of entry to the home with cation exchange resin, a type of ion exchange.

The best way to know if a product is actually capable of doing what it claims to do, Campbell said, is to look up its performance certifications. “You can do that in databases through the Water Quality Assn., the National Sanitation Foundation and the International Assn. of Plumbing and Mechanical Officials.”

The bare minimum

If nothing else, Stoiber urged consumers to peruse the EWG’s guide to countertop filters — and to purchase one.

Though McCurry is content drinking from the tap, he agreed it couldn’t hurt. “If you have reason to believe there are, say, PFAS above the future regulation target, then yeah, get a Brita filter,” he said.

Needless to say, that task is no longer on my to-do list.

Science

Contributor: Animal testing slows medical progress. It wastes money. It’s wrong

Published

1 day ago

February 2, 2026

Press Room

Contributor: Animal testing slows medical progress. It wastes money. It’s wrong

I am living with ALS, or amyotrophic lateral sclerosis, often called Lou Gehrig’s disease. The average survival time after diagnosis is two to five years. I’m in year two.

When you have a disease like ALS, you learn how slowly medical research moves, and how often it fails the people it is supposed to save. You also learn how precious time is.

For decades, the dominant pathway for developing new drugs has relied on animal testing. Most of us grew up believing this was unavoidable: that laboratories full of caged animals were simply the price of medical progress. But experts have known for a long time that data tell a very different story.

The Los Angeles Times reported in 2017: “Roughly 90% of drugs that succeed in animal tests ultimately fail in people, after hundreds of millions of dollars have already been spent.”

The Times editorial board summed it up in 2018: “Animal experiments are expensive, slow and frequently misleading — a major reason why so many drugs that appear promising in animals fail in human trials.”

Then there’s the ethical cost — confining, sickening and killing millions of animals each year for a system that fails 9 times out of 10. As Jane Goodall put it, “We have the choice to use alternatives to animal testing that are not cruel, not unethical, and often more effective.”

Despite overwhelming evidence and well-reasoned arguments against animal-based pipelines, they remain central to U.S. medical research. Funding agencies, academic medical centers, government labs, pharmaceutical companies and even professional societies have been painfully slow to move toward human- and technology-based approaches.

Yet medical journals are filled with successes involving organoids (mini-organs grown in a lab), induced pluripotent stem cells, organ-on-a-chip systems (tiny devices with human cells inside), AI-driven modeling and 3D-bioprinted human tissues. These tools are already transforming how we understand disease.

In ALS research, induced pluripotent stem cells have allowed scientists to grow motor neurons in a dish, using cells derived from actual patients. Researchers have learned how ALS-linked mutations damage those neurons, identified drug candidates that never appeared in animal models and even created personalized “test beds” for individual patients’ cells.

Human-centric pipelines can be dramatically faster. Some are reported to be up to 10 times quicker than animal-based approaches. AI-driven human biology simulations and digital “twins” can test thousands of drug candidates in silico, with a simulation. Some models achieve results hundreds, even thousands, of times faster than conventional animal testing.

For the 30 million Americans living with chronic or fatal diseases, these advances are tantalizing glimpses of a future in which we might not have to suffer and die while waiting for systems that don’t work.

So why aren’t these tools delivering drugs and therapies at scale right now?

The answer is institutional resistance, a force so powerful it can feel almost god-like. As Pulitzer Prize–winning columnist Kathleen Parker wrote in 2021, drug companies and the scientific community “likely will fight … just as they have in past years, if only because they don’t want to change how they do business.”

She reminds us that we’ve seen this before. During the AIDS crisis, activists pushed regulators to move promising drugs rapidly into human testing. Those efforts helped transform AIDS from a death sentence into a chronic condition. We also saw human-centered pipelines deliver COVID vaccines in a matter of months.

Which brings me, surprisingly, to Robert F. Kennedy Jr. In December, Kennedy told Fox News that leaders across the Department of Health and Human Services are “deeply committed to ending animal experimentation.” A department spokesperson later confirmed to CBS News that the agency is “prioritizing human-based research.”

Kennedy is right.

His directive to wind down animal testing is not anti-science. It is pro-patient, pro-ethics and pro-progress. For people like me, living on borrowed time, it is not just good policy, it is hope — and a potential lifeline.

The pressure to end animal testing and let humans step up isn’t new. But it’s getting new traction. The actor Eric Dane, profiled about his personal fight with ALS, speaks for many of us when he expresses his wish to contribute as a test subject: “Not to be overly morbid, but you know, if I’m going out, I’m gonna go out helping somebody.”

If I’m going out, I’d like to go out helping somebody, too.

Kevin J. Morrison is a San Francisco-based writer and ALS activist.

Science

A push to end a fractured approach to post-fire contamination removal

Published

5 days ago

January 30, 2026

Press Room

$A push to end a fractured approach to post-fire contamination removal$

The patchwork efforts to identify and safely remove contamination left by the 2025 Eaton and Palisades fires has been akin to the Wild West.

Experts have given conflicting guidance on best practices. Shortly after the fires, the federal government suddenly refused to adhere to California’s decades-old post-fire soil-testing policy; California later considered following suit.

Meanwhile, insurance companies have resisted remediation practices widely recommended by scientists for still-standing homes.

A new bill introduced this week by state Assemblymember John Harabedian (D-Pasadena) aims to change that by creating statewide science-based standards for the testing and removal of contamination deposited by wildfires — specifically within still-standing homes, workplaces and schools, and in the soil around those structures.

“In a state where we’ve had a number of different wildfires that have happened in urban and suburban areas, I was shocked that we didn’t have a black-and-white standard and protocol that would lay out a uniform post-fire safety standard for when a home is habitable again,” Harabedian said.

The bill, AB 1642, would task the state’s Department of Toxic Substances Control with creating standards by July 1, 2027. The standards would only serve as guidance — not requirements — but even that would be helpful, advocates say.

“Guidance, advisories — those are extremely helpful for families that are trying to return home safely,” said Nicole Maccalla, who leads data science efforts with Eaton Fire Residents United, a grassroots organization addressing contamination in still-standing homes. “Right now, there’s nothing … which means that insurance companies are the decision-makers. And they don’t necessarily prioritize human health. They’re running a business.”

Maccalla supports tasking DTSC with determining what levels of contamination pose an unacceptable health risk, though she does want the state to convene independent experts including physicians, exposure scientists and remediation professionals to address the best testing procedures and cleanup techniques.

Harabedian said the details are still being worked out.

“What’s clear from my standpoint, is, let’s let the public health experts and the science and the scientists actually dictate what the proper standards and protocol is,” Harabedian said. “Not bureaucrats and definitely not insurance companies.”

For many residents with still-standing homes that were blanketed in toxic soot and ash, clear guidance on how to restore their homes to safe conditions would be a much welcome relief.

Insurance companies, environmental health academics, and professionals focused on addressing indoor environmental hazards have all disagreed on the necessary steps to restore homes, creating confusion for survivors.

Insurance companies and survivors have routinely fought over who is responsible for the costs of contamination testing. Residents have also said their insurers have pushed back on paying for the replacement of assets like mattresses that can absorb contamination, and any restoration work beyond a deep clean, such as replacing contaminated wall insulation.

Scientists and remediation professionals have clashed over which contaminants homeowners ought to test for after a fire. Just last week, researchers hotly debated the thoroughness of the contamination testing at Palisades Charter High School’s campus. The school district decided it was safe for students to return; in-person classes began Tuesday.

Harabedian hopes the new guidelines could solidify the state’s long-standing policy to conduct comprehensive, post-fire soil testing.

Not long after the federal government refused to adhere to the state’s soil testing policy, Nancy Ward, the former director of the California Governor’s Office of Emergency Services, had privately contemplated ending state funding for post-fire soil testing as well, according to an internal memo obtained by The Times.

“That debate, internally, should have never happened,” Harabedian said. “Obviously, if we have statewide standards that say, ‘This is what you do in this situation,’ then there is no debate.”

Science

Expiration of federal health insurance subsidies: What to know in California

Published

5 days ago

January 29, 2026

Press Room

Expiration of federal health insurance subsidies: What to know in California

Thousands of middle-class Californians who depend on the state-run health insurance marketplace face premiums that are thousands of dollars higher than last year because enhanced federal subsidies that began during the COVID-19 pandemic have expired.

Despite fears that more people would go without coverage with the end of the extra benefits, the number enrolling in Covered California has held steady so far, according to state data.

But that may change.

Jessica Altman, executive director of Covered California, said that she believes the number of people dropping their coverage could increase as they receive bills with their new higher premiums in the mail this month. She said better data on enrollment will be available in the spring.

Altman said that even though the extra benefits ended Dec. 31, 92% of enrollees continue to receive government subsidies to help pay for their health insurance. Nearly half qualify for health insurance that costs $10 or less per month. And 17% of Californians renewing their Covered California policies will pay nothing for premiums if they keep their current plan.

The deadline to sign up for 2026 benefits is Saturday.

Here’s help in sorting out what the expiration of the enhanced subsidies for insurance provided under the Affordable Care Act, often called Obamacare, means in the Golden State.

What expired?

In 2021, Congress voted to temporarily to boost the amount of subsidies Americans could receive for an ACA plan. The law also expanded the program to families who had more money. Before the vote, only Americans with incomes below 400% of the federal poverty level — currently $62,600 a year for a single person or $128,600 for a family of four — were eligible for ACA subsidies. The 2021 vote eliminated the income cap and limited the cost of premiums for those higher-earning families to no more than 8.5% of their income.

How could costs change this year for those enrolled in Covered California?

Anyone with income above 400% of the federal poverty level no longer receives subsidies. And many below that level won’t receive as much assistance as they had been receiving since 2021. At the same time, fast-rising health costs boosted the average Covered California premium this year by more than 10.3%, deepening the burden on families.

How much would the net monthly premium for a Los Angeles couple with two children and a household income of $90,000 rise?

The family’s net premium for the benchmark Silver plan would jump to $699 a month this year from $414 a month last year, according to Covered California. That’s an increase of 69%, costing the family an additional $3,420 this year.

Who else could face substantially higher health bills?

People who retired before the Medicare-qualifying age of 65, believing that the enhanced subsidies were permanent, will be especially hit hard. Those with incomes above 400% of the federal poverty level could now be facing thousands of dollars in additional health insurance costs.

How did enrollment in Covered California change after the enhanced subsidies expired on Dec. 31?

As of Jan. 17, 1,906,033 Californians had enrolled for 2026 insurance. That’s less than 1% lower than the 1,921,840 who had enrolled by this time last year.

Who depends on Covered California?

Enrollees are mostly those who don’t have access to an employer’s health insurance plan and don’t qualify for Medi-Cal, the government-paid insurance for lower-income people and those who are disabled.

An analysis by KFF, a nonprofit that provides health policy information, found that nearly half the adults enrolled in an ACA plan are small-business owners or their employees, or are self-employed. Occupations using the health insurance exchanges where they can buy an ACA plan include realtors, farmers, chiropractors and musicians, the analysis found.

What is the underlying problem?

Healthcare spending has been increasing faster than overall inflation for years. The nation now spends more than $15,000 per person on healthcare each year. Medical spending today represents about 18% of the U.S. economy, which means that almost one out of every five dollars spent in the U.S. goes toward healthcare. In 1960, health spending was just 5% of the economy.

What has California done to help people who are paying more?

The state government allocated $190 million this year to provide subsidies for those earning up to 165% of the federal poverty level. This money will help keep monthly premiums consistent with 2025 levels for those with an annual income of up to $23,475 for an individual or $48,225 for a family of four, according to Covered California.

Where can I sign up?

People can find out whether they qualify for financial help and see their coverage options at the website CoveredCA.com.

What if I decide to go without health insurance?

People without insurance could face medical bills of tens of thousands of dollars if they become sick or get injured. And under California state law, those without coverage face an annual penalty of at least $900 for each adult and $450 for each child.