Tiny Dakota County town has a big problem: Polluted water

When Craig Franzmeier took over his family's farm in Coates in central Dakota County, he inherited a pesky, decades-old problem: polluted well water, teeming with nitrates that likely spring from farm fertilizers seeping into the sandy soil.

"It's always just been a fact of life for me," said Franzmeier. "When my kids were growing up, they couldn't drink the water at Grandma's."

Turns out that tiny Coates, with a population of only 160, is a pollution hot spot in Dakota County.

State studies indicate that up to 55 percent of the private wells used by Coates residents may have nitrate levels above drinking water standards. Consuming nitrates can cause blue baby syndrome, which can be fatal for infants.

The county also has found the breakdown products of cyanazine, a banned herbicide and known carcinogen, in the deepest Coates well tested.

Now with the help of a $10,000 county grant, Coates is researching the feasibility of hooking up to Rosemount's city water. Rosemount gets its water from aquifers, as does Coates. But the city has many wells and the water is safe, Rosemount Mayor Bill Droste said.

"I'd be completely open" to Coates using Rosemount's water, Droste said. "But of course it would come down to cost."

State Department of Agriculture data show that six out of 11 Coates wells tested between 2013 and 2015 had nitrate levels above the drinking water standard. A county analysis shows that two out of three wells tested in Coates have nitrates above the standard.

Longtime Coates resident Mike Gores spends $30 a month on bottled water. He supports connecting to Rosemount's pipes if it can be done affordably and provide enough water to fight fires.

"There's people out here who stick their head in the sand and say everything's fine, we don't care," Gores said. "But I think the more they're hearing about it, the more people are becoming aware."

Steve Scott, an environmental health specialist for Dakota County, agreed that there's growing awareness of the gravity of nitrates and herbicides in groundwater. But private wells, he said, "are kind of cut out of the loop."

Coates' water problems mirror issues found throughout Dakota County's rural areas, said County Commissioner Mike Slavik. At least 90 percent of the county gets its water from the ground through 150 municipal and 8,000 private wells, county data show.

Despite its growing suburbs, Dakota County still has a majority of its land — 52 percent — farmed for row crops like corn and soybeans, county officials said. As farmers do almost everywhere, Dakota County growers apply nitrogen fertilizer and herbicides to crops, some of which soak into aquifers below.

But the area's geology makes wells especially vulnerable to contamination, since water quickly trickles through the sandy soil and fractured limestone. Pesticides of the past can linger in the groundwater.

County officials started monitoring groundwater 19 years ago, periodically testing a sample of 70 wells. The result is an extensive data set that shows changes over time — including recent data showing that 60 percent of Dakota County wells tested are impaired with nitrates, manganese or degradates of cyanazine, with levels above drinking water standards.

"We don't know of any other place in the country where private drinking water wells are being tested for pesticides on a regular basis," said Jill Trescott, formerly the county's groundwater protection supervisor.

The agriculture department's township study found that 19 percent of Dakota County wells contained nitrates, a rate almost twice as high as the average in the state's farming areas, said state hydrologist Kim Kaiser.

Even if residents treat their water or drink bottled water, polluted wells are still a concern, Scott said, because they indicate declining ground­water quality.

And not everyone can afford to test or treat their water. Buying and maintaining reverse osmosis systems — the best treatment for ridding water of nitrates and cyanazine — can be expensive, Scott said.

Dakota County has made funding that will help residents pay for water treatment one of its legislative priorities, Slavik said.

Connecting Coates to Rosemount's water lines seems possible, Droste said, and makes sense because of expected future development.

But he said it would take some work. Rosemount has a water storage tank north of Coates and a pipe that runs along Hwy. 52 south to the city limits, but the pipe is too narrow and doesn't meet existing standards.

Locals have heard the idea before. Decades ago, the University of Minnesota extended a small water line out to 4,500-acre UMore Park in Rosemount. Some suggested that Coates link up to it, Gores said, but residents deemed it too expensive.

Money is often an obstacle for small towns when it comes to infrastructure. "It's hard to be able to have good systems when your population base is so small," Droste said.

County environmental staffers said their recent recommendations to the County Board included expanding public water systems when it makes sense economically.

"It would be a safe and reliable water source," said Vanessa Demuth, an environmental specialist with Dakota County. "It may be a challenge for the small town of Coates to cobble together … funding."

Some Coates residents buy bottled water or install reverse osmosis systems to filter what they drink.

Franzmeier, who is Coates' mayor, said his home has a filtering system to counter high nitrates. His family uses a Brita pitcher, which purifies water a second time. Though he tests his water with the county yearly, he estimated that less than a third of Coates residents do the same.

At the House of Coates, the city's lone restaurant, the water is tested annually and comes out fine, said owner Mike Bohn. But a sign on the bathroom door at the accounting firm of Rahn, Neisen and Root warns visitors not to drink the water.

Though Jake's Discount Liquor provides bottled water for workers, employee John Cline said he once tried a sip of tap water. "It's terrible," he said. "It will kill you."

Erin Adler • 612-673-1781