One of the responsibilities of the Environmental Protection Agency is imposing limits on the amount of harmful chemicals allowed in tap water. But sometimes these regulations aren't enough: In many of parts of the country, Americans are drinking water that passes the legal test but could still pose a threat to their health. Fortunately, checking local water contamination levels is easy for anyone with web access.

As Fast Company reports, the Tap Water Database from the Environmental Working Group, a nonprofit, non-partisan environmental health organization, provides the public with water-quality information on 50,000 utilities around the country. Visitors to the website can search for their local water facilities by state or zip code. Once they find those, they're directed to a list of chemicals that exceed the limits set by health professionals. Common contaminants like chloroform, nitrates, and trichloroacetic acid increase the drinker's risk of cancer if they're exposed to them over extended periods. Each report also includes chemicals that are present in the water supply but conform to the recommended health guidelines.

The tool is the only comprehensive and fully accessible database of its kind. Earlier in 2017, the website was updated for the first time in eight years with information collected from 2010 to 2015. But even if the data is a couple of years old, the resource is valuable to people who rely on their local utility for drinking water. This is especially true for people living in low-income neighborhoods where contamination levels tend to be highest.

Identifying the unwanted chemicals in your water can also help you get smart about purifying it at home. Different home purifiers are built to filter out different chemicals, which makes understanding the quality of your tap water before purchasing one essential. Here's our guide to picking the best water filter for your home.

[h/t Fast Company]