A survey of state data shows thousands of private wells in Iowa have been contaminated with nitrates and coliform bacteria. Under state law, most of Iowa’s private wells don’t have to be tested, and don’t have to meet water quality standards, leaving the residents who rely on them especially vulnerable.
Avon resident Janis Elliot began testing her private well about four years ago and says she has watched nitrate levels in her drinking water rise since then.
“The first year it tested 8, the next year it was 12, and the third year it was 19 parts per million of nitrates, and that’s almost twice the federal limit,” Elliot said. “So we’d been drinking poison basically, is how I felt.”
The U.S. Environmental Protection Agency’s legal limit for nitrates in drinking water is 10 parts per million (ppm). But a number of researchers have demonstrated levels as low as 5 ppm have been associated with increased risks of adverse health effects, including bladder, ovarian and colon cancer, and birth defects.
A review of 15 years of state data by the Environmental Working Group shows thousands of Iowans are seeing contamination from nitrates and coliform bacteria in their private wells, which the EWG researchers say is largely due to farm runoff from synthetic fertilizers and manure. It’s estimated 230,000 to 290,000 Iowans rely on private wells for their drinking water.
After going through with the testing, Elliot says she and her husband have since spent about $1,000 to install a reverse osmosis filtration system and a water softener. She acknowledges that kind of investment is out of reach for many Iowans, who might not be able to afford mitigation after learning their water is contaminated, or might decide to not test it at all.
"We could afford to get the reverse osmosis system and I wanted to know. But I certainly understand people who couldn’t afford that and wouldn’t want to know,” Elliot said.
Elliott is very aware of the potential health risks of nitrates. She’s been tracking cancer diagnoses in her neighborhood as well: ovarian, bladder and prostate, so far.
According to the EWG analysis, about 40 percent of wells tested had coliform bacteria, which is an indication E. coli may be present. Many strains of these indicator bacteria are naturally occurring and can but harmless, but according to EPA guidelines, there is no safe level of coliform bacteria in drinking water because they are associated with potentially harmful bacteria.
Additionally, about 12 percent of wells tested had nitrate levels at or above 10 parts ppm. About 22 percent had nitrate levels at 5 ppm, a threshold that researchers increasingly say is associated with a greater chance of health risks. In some hotspots, levels were at or above 100 ppm.
EWG economic analyst Anne Schechinger oversaw the analysis, which drew on data from the Iowa DNR’s Private Well Tracking System. She says the levels of nitrate contamination seem to be increasing over time.
“We’re seeing a lot of individual well tests that have really, really high numbers, really high nitrate tests," Schechinger said. "And we’ve seen almost all of those, I think it’s around 70 or 80 percent, happened in the last ten years."
Schechinger says the data showed certain factors are associated with higher levels of contamination; shallow wells are more prone to pollutants, and bacteria levels tend to be higher during the summer months.
While EWG analyzed data from about 55,000 wells, the survey does not account for all of the state’s wells. Under state law, existing private wells don’t have to be screened, though newly built or renovated wells are tested, and state officials recommend all residents test their private wells once every year.
“The groundwater that supplies your well can become contaminated through natural processes and human-related activities,” reads a statement on the DNR’s website. “Even if you believe that your well is safe to drink, it’s important to periodically sample and test your water to assess any health related concerns that water may create […] At a minimum, we recommend bacteria and nitrate testing be performed at least once per year.”
But EWG’s analysis shows annual monitoring of private wells is largely not happening; according to the recently published report, just 12 wells were tested for coliforms every year and just 10 wells were tested for nitrate every year. While the state allocates funding to counties to pay for testing that residents request, implementation varies widely.
Between 2003 and 2017, Decatur, Wayne, Sioux and Osceola Counties each conducted fewer than 10 tests for nitrates or coliform under the Grants to Counties program. Marshall County does not participate in the program at all.
Schechinger says not regulating private wells leaves many rural residents unaware of the potential risk. While public water systems are required by law to notify their customers of certain levels of contamination, she says some private well owners may never know what could be in their water.
“No one really regulates wells. It’s really on the homeowners to keep their wells safe,” she said. “Those of us who are on public water systems, we just rely on our water utilities to give us safe water. But then when private wells aren’t regulated the people on private wells don’t really know what’s safe and what’s not safe.”
The Environmental Working Group is calling on state leaders to make changes to the Grants to Counties program, namely requiring that counties participate, and freeing up funding to be used for mitigation as well as testing.
“We’ve heard a lot of people say that they are worried about having their water tested because they couldn’t afford to fix the problem if they find it,” Schechinger said. “No one should be drinking unsafe water because they can’t afford to fix the problem.”
EWG is also calling on state lawmakers to require farmers to adopt conservation practices to keep pollutants out of Iowa’s waterways.
State lawmakers have implemented a voluntary Nutrient Reduction Strategy, aimed at ultimately cutting Iowa’s nutrient load by 45 percent. Agriculture Secretary Mike Naig says state leaders are committed to reaching water quality goals and are encouraged by public and private efforts to adopt conservation practices like planting cover crops, reducing tilling and restoring wetlands.
But Janis Elliot says voluntary measures are not enough to keep nitrates out of the drinking water in her unincorporated community in south Polk County. She supports the idea of more state regulation, saying farmers are putting “a whole community at risk."
Even after installing a reverse osmosis filter to remove nitrates in her home, Elliot says water quality is still a concern for her and her grown children, who are raising their own kids on the West Coast.
"When I talk to my children on the West Coast about moving back to Iowa, their response is: ‘well not with that water!’” she said. “They’ve both got young kids and…just wouldn’t come back.”