Source: POLITICO'S MORNING AGRICULTURE, 10/3/18

Nitrate contamination in public water systems is a widespread problem across the country, but the scourge is really taking a toll on small communities that may not be able to pay for a treatment system, according to a new report from the Environmental Working Group.

Nitrate levels considered by the National Cancer Institute to increase the risk of cancer were found in 1,700 communities in the U.S., and two-thirds of those have no treatment systems to lower nitrate concentrations to safer levels. Within that subset, according to federal data, more than six out of 10 water systems serve 500 or fewer people, and nearly nine out of 10 serve fewer than 3,300 people.

A question of standards: The National Cancer Institute's standard for determining unsafe nitrate levels is lower than the one used by the EPA. The legal limit for safe drinking water is 10 parts per million, or 10 ppm. But recent research from the institute shows that tap water containing 5 ppm of nitrate increases the risk of colon, kidney, ovarian and bladder cancers.

Water treatment systems are expensive: EWG estimated that the cost to build an effective system in these small communities could total hundreds or thousands of dollars a year, per person. Agriculture is by far the biggest contributor to nitrate pollution. Water systems without proper nitrate treatment are mostly found in farming areas in the Midwest and California with less than 500 residents, but still exist in 43 states.

"Without aggressive, targeted and enforceable protection efforts, America's nitrate problem will get worse, and more Americans will be at risk of drinking contaminated water," EWG states. You can find the full report here.