Data compiled by a non-profit environmental advocacy organization shows different sources of tap water face different challenges in keeping it clean.
The Environmental Working Group created a searchable database of more than 50,000 water utilities across the country. The utilities are rated based on the EWG’s recommendations for safe contaminant levels — not on federal or state regulations.
EWG researcher Sydney Evans said that’s because many of those standards are outdated.
“What we’re finding is that legal does not necessarily equal safe,” Evans said. “Some standards are more than 40 years old. A lot of those take into account the technology that was available at the time, the treatments that were available at the time and the cost, in addition to some outdated health science.”
According to Evans, utilities that use surface water — like rivers or lakes — have to use a lot of disinfectants to keep their supply pathogen-free.
“But when that disinfectant is added to the water that already has other contaminants and organic matter — like vegetation, algae, manure — it’s going to combine and form a number of disinfectant byproducts, which can increase the risk for bladder cancer,” she said.
Evans said farming communities experience elevated levels of nitrates due to agricultural run-off. Meanwhile, the burden of keeping water clean can be more strenuous on small communities.
“A lot of the smaller systems that tend to rely on groundwater, they struggle to have higher water quality because the resources and the infrastructure just aren’t in place,” she said. “They don’t have the economy of scale.”
The EWG database also includes information meant to help consumers choose a filter to reduce contaminants in their specific water source.
“We want to give people this resource as something they can do now,” Evans said. “However, ultimately, we advocate for community level change and national level change to tighten these regulations.”
Search the full EWG database here.