Each year, millions of Americans suffer the effects of illnesses related to contaminated drinking water. Here’s how to keep yourself from becoming one of them.

Contaminated drinking water is a public health risk, and lead is just one threat. Drinking water can be contaminated with microbes, minerals, metals, radon, chemicals from treated sewage, industrial chemicals, and agricultural chemicals including nitrates, atrazine and other pesticides. But ironically, the most common contaminants are by-products of adding chlorine to disinfect water. According to the CDC, there are at least 600 “disinfection by-products,” including chloroform and bromodichloromethane, both possible carcinogens.

So why are we still using chlorine in our drinking water? Chlorine is the most common method used in the US to disinfect water for a number of reasons. It has been in use for a long time…it’s good at killing most pathogens in water…and if you add enough chlorine for there to be residual chlorine in the water, it continues to work as the water flows through pipes. But here’s the problem—that chlorine also continues to form those by-products.

There are alternatives for treating water including ozone, ultraviolet light and membrane filtration, but none of those methods allows for residual treatment, and each alternative has its own challenges. So at least for the time being, chlorine is still considered the best option for large-scale water disinfection.


Many of the problems in our drinking water originate from fundamental problems that are complicated and expensive to address…

Aging infrastructure. Water pipes in many areas of the US are 50 to 100 years old—sometimes even older—corroded and filled with bacteria. They contain lead, too (see below). Treatment plants may be just as old, and most rely on technologies from the early 1900s.

Regional issues. Your drinking water is affected by many variables, from the source of the water to how it’s treated and distributed where you live, all of which will determine what contaminants are most likely to be found in your local supply.

Chemical contaminants that aren’t regulated. Water utilities and the Environmental Protection Agency (EPA) are tasked with addressing the issues that affect drinking water, but regulating chemicals is a very complicated process. The way regulation works is that the EPA doesn’t list what can be in drinking water—it has to say what specifically cannot. The problem is that the list of chemicals that it would be better not to have in drinking water is potentially in the many thousands. Deciding what actually gets on the EPA list takes a lot of time and money, so most chemicals will not be added, at least not anytime soon.

Volume of water that must be treated. The EPA states that all the water going into your house must meet the health standard for drinking water even though 99% of that water goes for other uses such as bathing, washing your car, flushing down the toilet and doing laundry. The sheer volume of water that has to be treated makes it too expensive to meet a higher standard of quality for our drinking water.

Lead pipes. The recent problem of widespread lead contamination that occurred in Flint, Michigan, is not limited to Flint. Houses built before 1986 (the year the EPA banned lead pipes and fixtures made with lead) may still have lead pipes, brass fixtures that contain lead and lead solder. Because the EPA can’t force people in older homes with lead pipes to change them, it tries to control how corrosive our drinking water is—the more corrosive, the more it causes lead from pipes to leach into water. A change in the Flint water supply caused a significant change in the corrosiveness of the water—lead that had been slowly leaching into the water suddenly started leaching quickly, leading to lead exposure for many people, including children. This can happen in any area that has older homes and, even if you don’t have a lead pipe to your water main, the pipes and fixtures may still contain lead.

Climate change. Climate change leads to more droughts and more extreme “water events” such as floods and torrential hurricanes, all of which have significant effects on water quality that can be short-lived or long-lived. This will likely only get worse over time.


Most water utilities have some violations of the safety standards during the course of a year, so the number-one recommendation is to add a point-of-use filter to the faucet that provides your water for drinking—for most people, this means at their kitchen sink. A filter gives you that next level of quality that everyone should have in drinking water. Also, keep in mind that water is regulated as it’s coming out of a treatment plant…it then gets sent through potentially miles of pipes before it reaches your faucet.

If you have lead pipes, replacing them could mean ripping up a lot of your house. Most people can’t afford to do that unless it’s part of a major home renovation that’s being done anyway. A properly selected filter can remove most if not all of the lead that leaches into your water from pipes.

There are two general types of filters…

A cartridge filter is usually “activated carbon”—the carbon, or charcoal, in the filter attracts and captures impurities as water passes through it—that your water filters through. It significantly reduces most contaminants including, for selected filters, lead.

A reverse osmosis filter is a membrane that takes virtually everything out. It is more expensive than a cartridge filter—from over $100 for a single-sink system to over $1,000 for a whole house system plus $100 to $200 a year for replacement filters, and you may need a plumber to install it. However, if you’re a woman who’s pregnant or could become pregnant or have young children in the house, it’s worth investing in this kind of filter because contaminants have a much greater effect on developing embryos and small children.

One more step before buying a filter: Read the water report your water company sends out every year and look specifically for any violations it had. Choose a filter that lists that contaminant among all the ones it filters out (this information will be listed on the box).

You might be wondering whether, with all these possible contaminants in your drinking water, you should just buy flats of bottled water or a dispenser that uses large, multiple-gallon jugs. The same regulations that apply to water utilities apply to bottled water manufacturers. Most of these manufacturers either find a very pure source or use reverse osmosis filtration to purify the water, so it does tend to be more pure than tap water. However, it is an expensive alternative to a filter and it has a significant environmental impact related to all the plastic used for the bottles and jugs and the inefficient transport of heavy bottles of water by trucks.


If you get your water from a large municipality, the water utility is testing it constantly. Unless you’d be testing it for something specific, it’s hard to know where to begin since there are thousands of possible contaminants. Also, you would be testing just one sample at one particular point in time, so it is unlikely you would find anything at that moment. However, if you know of a problem in your area regarding a specific contaminant (remember, that’s why you’re reading through those annual water reports), you could test your water for that.

If you get your water from a small municipality, you have even more reason to check your utility’s water reports for violations and install a point-of-use filter in your home. A February 2018 study published in Proceedings of the National Academy of Sciences found that water utilities in smaller, more rural and lower-income communities had more violations than utilities in larger, more urban areas with more money. Consider testing your water on your own, especially if there’s been an outbreak to see if it was resolved.

If you have a private well, your water likely won’t be tested nearly as frequently as with any municipal system. Testing varies by community and in some areas it is never done by the government, making it your responsibility to check for yourself. Contact the local agency responsible for the safety of private wells in your area (possibly the state department of natural resources or the health department) and ask whether they’re aware of any contaminants being found in local wells and what they are. If there are any farms or big industries around you that result in coliform bacteria, nitrates or other chemicals contaminating the ground water, he recommends hiring a company to test your well water for you. Ask your local agency for a recommendation of a water testing company, when to test, and how often to test.

One more thing…to ensure safe drinking water, elect public officials who you know understand the importance of protecting our water supplies.

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