How can you tell if your tap water is safe? How does tap water get contaminated? Ask Science explains what contaminates our water, how it gets there, and what we can do to test it.
The tap water we drink, cook with, and bathe in typically comes from either surface water sources like streams, rivers, lakes, and reservoirs, or from underground sources like aquifers, permeable rocks that can store and transmit water. A range of dangerous pollutants have been found in this water, including bacteria like e. coli, toxic algae, lead, sulfur, excess iron, and general dirt and grit, that are known to lead to a host of health issues from gastrointestinal problems to neurological disorders, as well as reproductive issues.
So how do these contaminants get in our water in the first place? And how can you, as an individual, know whether or not your tap water is safe for you and your family to drink?
How Does Drinking Water Become Contaminated?
According to the Center for Disease Control, the most common sources of contamination in the US water system are related to local land uses and manufacturing processes. For example, fertilizers and pesticides used on farmland as well as contributions from livestock, can leak into surface water sources if not carefully monitored. Sewer overflows as well as any malfunctions in septic systems can also lead to contamination. Some other chemicals, like arsenic, occur naturally and so their levels also need to be checked.
Ironically, massive rain can also affect the supply of clean water. Earlier this month, 1.5 million Chileans living in the city of Santiago were left without water because massive amounts of rain led to mudslides and flooding which brought contaminants into the Maipo River, a major source of drinking water there.
See Also: Should You Drink Tap or Bottled Water?
How Do I Know If My Drinking Water Is Safe?
In the U.S., keeping our drinking water safe from contaminants is largely the job of the Environmental Protection Agency. Luckily, the EPA has a variety of programs and searchable maps that make checking the contaminants in your water as simple as typing in your zip code or picking up the phone to dial their hotline. However, the EPA is facing huge proposed budget cuts under the current administration which puts many of these programs at risk.
See Also: What Does the EPA Do?
Here are a few ways you can investigate the safety and quality of the drinking water in your home, in order of the amount of work it will take you to check!
1. Check the EPA’s website. The EPA has several tools for checking the status of your drinking water, including the Safe Drinking Water Information System which reports any known violations of EPA’s water regulations, as well as information on monitoring requirements and treatment efforts. You can also learn more about the maximum levels of different contaminants that are permitted.
And if you use well water, do not fear—the EPA also has a guide for privately-owned wells.
2. Thanks to differences in reporting requirements from state to state, assessing the relative contaminant risk in your water can be challenging. That’s why some researchers have made efforts to combine information from as many sources as possible and report the data in a consistent way.
For example, last year vox, with help from the Washington State Department of Health, published a lead exposure map searchable by address (not just by city). There I can see that, on a scale of 1 to 10 with 1 being little to no risk but 10 being the highest risk of lead contamination levels, my county scores a 3 on average and my city varies between 5 and 10, but my neighborhood is at an 8. Yikes!
3. Look for resources on specific contaminants. If you are concerned about a specific contaminant, you may be able to more efficiently search for resources highlighting that specific issue. For example, it is estimated that over 200 million Americans have tap water with levels of chromium-6 that are higher than what is considered an acceptable maximum level. If you’ve seen the movie Erin Brockovich, then you know what this chemical can do.
The ultimate method for testing your home’s drinking water is to have it tested yourself.
The Environmental Working Group has a map of the level of contamination from chromium-6 found in almost every city in the U.S. including details on how often and where the water has been tested. Just typing in my zip code tells me that, while the goal is to keep chromium-6 levels below 0.02 parts per billion (ppb) my city averages 0.22 ppb. Yikes again!
4. Ask your water company. Did you know that your water company is required by the EPA to report to you every year on the quality of your water? If you receive a bill in the mail, you likely receive this report via snail mail as well. However, if like many of us you’ve switched over to e-billing to save a few trees, then you may have to do a little more digging online to find it. To make the search a bit easier, the EPA has a map to help you find the report from the water company in your area and the CDC has a a guide to help understand all of the information in these so-called “Consumer Confidence Reports”.
5. Test your water yourself. The ultimate method for testing your home’s drinking water is to have it tested yourself. A quick call to the EPA’s Safe Drinking Water Hotline can offer you names of water testing agencies in your area. You can also purchase home test kits, but they are usually recommended for tracking changes in your water supply, say for example, if you are treating your water and want to check the progress, and not for ultimately determining the safety of your water.
If you want to know about taking action to safeguard your tap water, check out this post from Nutrition Diva on what your those Brita filters can and cannot remove from your water supply.
Until next time, this is Sabrina Stierwalt with Ask Science’s Quick and Dirty Tips for helping you make sense of science. You can become a fan of Ask Science on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at email@example.com.