What Contaminants Are in Tap Water?

slug: what-contaminants-are-in-tap-water

title: "What Contaminants Are in Tap Water?"

teaser: "From 'forever chemicals' to lead pipes, here is exactly what might be hiding in your daily glass of water."

category: water-filtration

subcategory: understanding-your-water

verdict: caution

status: published

is_new: true

updated: 2026-03-03

tldr: >

Most US tap water meets federal standards, but legal doesn't always mean safe. Common contaminants include PFAS ("forever chemicals"), which are found in nearly half of US faucets, and lead from aging infrastructure. Chloramine, nitrates, and carcinogenic byproducts are also widespread. A simple carbon filter often isn't enough—you likely need reverse osmosis or catalytic carbon to be truly safe.

key_findings:

• "Forever chemicals" (PFAS) are present in 45% of US tap water sources.
• 9 million lead service lines still connect homes to water mains in the US.
• Over 250 million Americans are exposed to Chromium-6 (the "Erin Brockovich" chemical).
• Disinfection byproducts (like THMs) are linked to bladder cancer and are found in most chlorinated systems.

sources:

• title: "PFAS in US Tap Water"

url: "https://www.usgs.gov/news/national-news-release/tap-water-study-detects-pfas-forever-chemicals-across-us"

type: study

• title: "EPA Lead Service Line Estimate"

url: "https://www.epa.gov/ground-water-and-drinking-water/lead-service-lines"

type: fda

• title: "EWG Tap Water Database"

url: "https://www.ewg.org/tapwater/"

type: lab-test

recommendations:

• name: "AquaTru Reverse Osmosis"

brand: "AquaTru"

verdict: recommended

note: "Removes PFAS, lead, nitrates, and chromium-6 effectively."

• name: "Hydroviv Under Sink"

brand: "Hydroviv"

verdict: acceptable

note: "Customized carbon filter that targets your specific city's contaminants."

• name: "Brita Standard Pitcher"

brand: "Brita"

verdict: avoid

note: "Misses too many critical contaminants like lead, PFAS, and nitrates."

related:

• is-tap-water-safe-to-drink
• what-is-pfas-in-water
• is-there-lead-in-my-tap-water
• is-chlorine-in-tap-water-harmful
• what-is-the-best-home-water-test-kit

suggested_articles:

• title: "Does Boiling Water Remove Contaminants?"

reason: "Readers often assume boiling fixes everything, but for PFAS and lead, it makes things worse."

• title: "How to Read Your City's Water Quality Report"

reason: "People get these reports in the mail but don't know how to spot the red flags."

The Short Answer

Your tap water is likely "legal" but not necessarily "safe." While the US has some of the cleanest water in the world, federal regulations haven't kept pace with modern science. The EPA regulates over 90 contaminants, but thousands of chemicals—including many PFAS variants and pharmaceutical residues—have no legal limits at all.

The most concerning contaminants found today are PFAS ("forever chemicals"), lead from old pipes, nitrates from farming, and disinfection byproducts that form when chlorine reacts with organic matter. Is City Tap Water Actually Safe To Drink explains that meeting a "Maximum Contaminant Level" (MCL) is often a compromise between public health and the cost of treatment, not a guarantee of zero harm.

Why This Matters

What you can't taste can hurt you.

Many of the most dangerous contaminants, like lead and PFAS, are completely tasteless and odorless. You cannot rely on your senses to detect them. By the time you notice a funny smell (usually chlorine or sulfur), you're dealing with aesthetic issues, not necessarily the most toxic ones. What Is Pfas In Water details how these invisible chemicals accumulate in your body over decades.

Infrastructure is crumbling.

Even if water leaves the treatment plant clean, it has to travel through miles of pipes to reach you. Lead service lines and corroding distribution systems can re-contaminate water just yards from your house. Is There Lead In My Tap Water dives into why this is a massive problem for homes built before 1986.

Disinfection has a dark side.

We add chlorine and chloramine to kill bacteria, which is essential. But these chemicals react with natural organic matter (like leaves in a reservoir) to create Disinfection Byproducts (DBPs). These byproducts are potentially carcinogenic and are regulated, but often spike seasonally. Is Chlorine In Tap Water Harmful covers this trade-off in depth.

What's Actually In Your Tap Water

Here are the specific villains hiding in US municipal water supplies.

• PFAS ("Forever Chemicals") — Found in 45% of US tap water. Linked to cancer, hormone disruption, and immune system damage. New EPA limits set in 2024 are strict (4 parts per trillion), but removal takes time. What Is Pfas In Water
• Lead — A potent neurotoxin with no safe level for children. It leaches from old service lines and brass fixtures. EPA estimates 9 million lead pipes are still in use. Is There Lead In My Tap Water
• Nitrates — Common in agricultural areas due to fertilizer runoff. Dangerous for infants ("blue baby syndrome") and linked to thyroid disease and colon cancer in adults. Standard carbon filters do not remove this. What Minerals In Water Are Bad For You
• Chloramine — A mix of chlorine and ammonia used by 20% of Americans' water systems. It lasts longer in pipes than chlorine but is harder to filter out, requiring catalytic carbon. Is Chlorine In Tap Water Harmful
• Chromium-6 — The "Erin Brockovich" chemical. Carcinogenic even at low levels. Found in the tap water of 250 million Americans, often from industrial pollution.
• Trihalomethanes (THMs) — A group of cancer-causing chemicals formed when chlorine reacts with organic matter. If your water report lists "TTHMs," this is what they are.
• 1,4-Dioxane — A likely carcinogen used in solvents. It’s hard to detect and even harder to remove (requires reverse osmosis).
• Microplastics — Tiny plastic fragments found in 94% of US tap water samples. They act as "rafts" for bacteria and leach chemicals into your body.

What to Look For

When reading your Annual Water Quality Report (Consumer Confidence Report), look for these signals.

Green Flags:

• "Non-Detect" (ND) — Ideally, you want to see ND for lead, arsenic, and VOCs.
• Low TTHMs — Total Trihalomethanes should be well below 80 ppb (parts per billion). Ideally below 10 ppb.
• Recent Testing — Data should be from the current or previous year. Old data (3+ years) is a warning sign.

Red Flags:

• "Total Chromium" only — Utilities often report "Total Chromium" to hide high levels of toxic Chromium-6.
• High Nitrates — Anything over 5 mg/L (half the legal limit) is concerning for sensitive groups.
• 90th Percentile Lead > 0 — Even if they pass compliance, any detected lead means some homes have a problem.
• "Monitoring Violation" — This means they didn't test when they were supposed to. If they aren't testing, assume the worst.

The Best Options

To remove these specific contaminants, you need more than a standard pitcher filter.

The Bottom Line

1. Test your water. Don't guess. Use a third-party lab service like Tap Score to see exactly what is coming out of your specific faucet. What Is The Best Home Water Test Kit

2. Filter for your worst contaminant. If you have nitrates, you must use Reverse Osmosis. If you have chloramine, you need catalytic carbon.

3. Ignore the "Legal" label. Just because your city meets EPA standards doesn't mean the water is optimal for your long-term health.

FAQ

Does boiling water remove contaminants?

No. Boiling kills bacteria, but it actually concentrates heavy metals like lead and chemicals like PFAS as the water evaporates. Never boil water to remove chemical contaminants. Does Boiling Water Remove Pfas

Can I absorb contaminants through my skin in the shower?

Yes. Chlorine, chloramine, and volatile organic compounds (VOCs) can be inhaled or absorbed through skin during a hot shower. A shower filter is recommended if you have high chlorine levels.

How do I know if I have lead pipes?

Check your service line. Locate where the water pipe enters your home (usually the basement or crawl space). If the pipe is soft, dull gray, and scratches easily to reveal a shiny silver color, it is likely lead. Is There Lead In My Tap Water