The entire country has been watching in shock as the ongoing water crisis in Flint, MI has unfolded. But a new investigation from the USA Today Network reveals that lead contamination of drinking water extends far beyond Flint, and that the government's response to the problem has been insufficient.After analyzing U.S. Environmental Protection Agency (EPA) data, the news organization found that nearly 20% of the nation's water systems test above what's known as the Lead and Copper Rule " action level " of 15 parts per billion, which is essentially experts' best guess at the point where lead levels in water can start to cause health problems. Worse, the organization's analysis found that 350 schools and daycare centers nationwide failed lead tests roughly 470 times from 2012 through 2015.Lead exposure is particularly dangerous for children and babies because they are still developing. Research shows that even low levels of lead in children's blood can have developmental effects, such as a lowered IQ, attention deficit disorders, and learning problems, according to the U.S. Centers for Disease Control and Prevention (CDC). For the most part, these effects are irreversible once exposure happens.For adults, low levels seem to be less dangerous, but over time exposure can allow lead to build up in the body, causing a range of symptoms such as high blood pressure, headaches, abdominal pain, mood disorders, and more, according to the Mayo Clinic. Symptoms often don't start until the level is dangerously high.Drinking water is not the only way lead can find its way into your system. In fact, the more common source of exposure is lead paint. Although lead has not been used in paint since the late 1970s, it remains in many older homes and buildings, where it can peel off and create dust that you might breathe in. It also occurs naturally in soil.Lead gets into the water supply mainly because many municipal and household water systems have old pipes that contain lead soldering. If the water source is corrosive (which is what happened in Flint ) the water can pick up lead from the soldering as it flows through the pipes. If water sits for long periods in the pipes (like it does when school is out for the summer), this can also up the risk that lead will get into the water.Various regulations, including the Reduction of Lead in Drinking Water Act and The Lead And Copper Rule , mandate that lead levels in the drinking water supply be monitored so that if problems arise, actions can be taken. But the USA Today investigation points out holes in these regulations. For example, most school districts and childcare facilities are not required per the Safe Drinking Water Act to test for lead in the water coming out of, say, drinking fountains and cafeteria kitchens.And if the failure in Flint proves anything, it's that even with testing, the response isn't always fast enough to keep people safe. For its part, the USA Today investigation cites instances in New York, Arizona, and Pennsylvania where certain schools' water failed lead tests, yet it took months, even years in some cases, to warn parents, provide bottled water, and replace faucets or pipes that had lead in them. (Seriously, go read the full story here ; it's jaw-dropping.)This is probably not the last time you'll be hearing about this issue, but if you're totally freaking out right now, the good news is that there are some things you can do now to find out what's in your water. By law, every community water system is required to provide an annual report to residents that details the water source and contaminant levels. This report, called a Consumer Confidence Report or "CCR," should show up along with your water bill every July. If you haven't received one (possibly because you don't own your home and your landlord pays the water bill) you can look up your CCR here You can also always have your water tested directly in your home — call the EPA's safe drinking water hotline and they can help you find an appropriate service to use in your area. You can find out about lead in your pipes by calling your water authority and simply asking . And finally, the CDC has even more advice about what to do should you discover a source of lead in your water. Aside from only using bottled water (which may, in fact, be warranted), "flushing" your pipes, installing a filtration system, and only drinking or cooking with cold tap water can help reduce exposure.