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The Chemicals No One Talks About in Your Water
Most of us never question what comes out of the faucet. We expect it to be clean, safe, and healthy. And in many ways, it is.
Modern water treatment wiped out deadly diseases like cholera and typhoid that once claimed thousands of lives. But there’s a hidden downside few people know about—the chemicals created when disinfectants like chlorine do their job.
Where Our Water Comes From
Your drinking water depends on where you live. Big cities usually pull from lakes, rivers, or reservoirs. Small towns often rely on underground wells. In drier places, some systems even recycle wastewater or stormwater.
Groundwater is naturally filtered as it moves through soil and rock, so it often needs less treatment. Surface water, on the other hand, carries more contaminants and requires stronger chemical treatment to make it safe.
How Water Gets Treated
Before it reaches your tap, water goes through several steps:
- Coagulation and flocculation: Added chemicals grab dirt and tiny particles, clumping them together.
- Sedimentation: The heavy clumps sink, leaving cleaner water on top.
- Filtration: Sand, gravel, or membranes strain out the rest, including parasites and bacteria.
- Disinfection: Finally, chlorine, chloramine, or another disinfectant is added to kill germs and keep the water safe as it travels through pipes.
This process saves lives—but it creates new problems.
The Unseen Threat: Disinfection Byproducts
When disinfectants react with natural material in water—like leaves, soil runoff, or even human waste—they form new chemicals called disinfection byproducts (DBPs).
The EPA regulates only four: trihalomethanes (THMs), haloacetic acids (HAAs), chlorite, and bromate. But scientists believe there are hundreds more that remain unregulated and poorly studied.
In fact, DBPs are often found at levels 100 to 1000 times higher than other well-known pollutants like pesticides.
The Health Risks
Research is increasingly linking DBPs to health concerns:
- Bladder cancer: Long-term exposure raises the risk, especially in men. A 2024 study found a 33% higher risk of bladder cancer even when DBPs were under legal limits.
- Colorectal cancer: The same study found a 15% higher risk.
- Pregnancy complications: Some studies connect DBPs to miscarriages, stillbirths, and low birth weight.
- DNA damage: Lab tests show many DBPs can harm DNA and cells.
The problem is that most DBPs aren’t studied or monitored. Worse, new ones can form as treated water moves through pipes on the way to your home.
Why Chlorine Is Still Used
If DBPs are risky, why not ditch chlorine? Simply put—because nothing else protects water as effectively once it leaves the plant. Without it, germs could spread through the miles of pipes that carry water to our homes. Chlorine prevents outbreaks of diseases far worse than DBPs.
So the real challenge is reducing DBPs without losing that protection.
What Utilities Are Doing
Some water systems are upgrading to advanced purification methods like activated carbon or high-pressure membranes—the same technologies used to remove PFAS “forever chemicals.” These can cut DBPs almost in half.
But so far, only about 8% of utilities use them. Cost and infrastructure remain big roadblocks.
What You Can Do at Home
Even if utilities are slow to change, you can reduce your own exposure:
Use Filters
- Activated carbon filters can trap some DBPs.
- Reverse osmosis (RO) filters are even more effective, removing both organic and inorganic byproducts.
- Pitcher filters are less powerful but still helpful at a low cost.
Store or Boil Water
- Refrigerating tap water in an open pitcher for 24 hours can cut trihalomethanes by nearly half.
- Boiling for just one minute, then cooling, can remove up to 92% of certain DBPs.
Know Your Source
Groundwater often has fewer DBPs than surface water. But if you use a private well, make sure to test it regularly.
Read Your Water Report
Every year, your utility must provide a Consumer Confidence Report listing contaminants—including DBPs, lead, nitrates, and PFAS. You can request it directly or find it on the EPA’s site.
Balancing Safety and Risk
There’s no question—untreated water is far more dangerous than DBPs. Chlorination has saved countless lives over the last century. But the hidden risks remind us that the system isn’t perfect.
The best approach is a balance: keep supporting utilities as they modernize treatment while taking simple steps at home to protect your family.
Final Word
America’s tap water is generally safe, but it often carries hidden chemical byproducts from treatment. These chemicals may increase risks for cancer and pregnancy complications, even when levels meet federal standards.
You can’t avoid them entirely… but with filters, storage, boiling, and knowledge of your local water, you can lower your exposure. Clean water is one of modern life’s greatest blessings. It’s worth the effort to make sure it stays safe for the long run.
