Manure has been blamed for much of the bacteria and viruses that pollute Wisconsin drinking water, but contamination from human waste is a problem, too.

Failing septic systems, leaking public sewer pipes and landspreading of septic waste can introduce dangerous pathogens into both rural and urban water systems.

In June 2007, 229 people were sickened by a norovirus in Door County while eating at a restaurant. Seven were hospitalized as a result of a pathogen known for spreading illness on cruise ships. The source: a leaky septic system.

In 2012, a microbiologist published research that linked widespread gastrointestinal illnesses in 14 Wisconsin communities to viruses in the public water systems. Further research showed the contaminants were likely coming from leaking municipal sewage lines.

That same year, the Wisconsin State Journal reported that top Department of Natural Resources officials went easy on a political supporter of Republicans, including Lt. Gov. Rebecca Kleefisch, after the donor was caught violating septic waste spreading rules on fields near 40 drinking water wells, potentially exposing residents to nitrate, which can cause “blue baby syndrome,” and illness-causing pathogens.

In 1993, Wisconsin experienced the most deadly waterborne disease outbreak in U.S. history. One hundred people died and 403,000 became sick in Milwaukee when cryptosporidium contaminated the city’s drinking water. Lab tests confirmed the parasite had come from human waste.

Some experts say the state’s septic regulations and well standards are not adequate to protect public health in areas of Wisconsin with fractured bedrock, such as Door County.

Coburn Dukehart / Wisconsin Center for Investigative Journalism

In addition, municipal water systems in Wisconsin are not required to test for or treat water to kill viruses because the Legislature in 2011 rescinded a rule that would have mandated such action. And a study by a retired hydrogeologist has found that the state sometimes fails to enforce regulations that ban spreading untreated septic waste on fields vulnerable to groundwater pollution.

Septic systems are the main line of defense in rural areas against water contamination from human waste. The potentially lethal waterborne disease outbreak at a new restaurant in Door County in June 2007 illustrates the weakness of existing regulation, especially in areas with fractured bedrock.

Courtesy of the Door County Sanitarian's Department

In a 2011 paper in the journal Ground Water, a team of Wisconsin scientists investigated the outbreak, which began with four employees who got acute gastroenteritis. The virus that caused the sickness also was detected in the restaurant’s new water well and septic system.

Researchers concluded that the cracked bedrock under the restaurant, which is common in eastern Wisconsin, allowed waste from the broken septic system to move rapidly into the restaurant’s drinking water well.

The scientists noted that Door County and other areas that sit atop such karst geology have long dealt with the vulnerability of their fractured limestone aquifers to such contamination. They cited a Nov. 22, 1955, headline from the Door County Advocate newspaper warning that local geology had been tied to cases of “summer flu.”

Most residents, the researchers wrote, assume that waste from septic systems is biodegraded by soil on the way down to the groundwater and then safely diluted. But that is not always true.

Experts: Stricter rules needed

The researchers recommended that the state should reconsider allowing conventional septic systems to be built above fractured limestone aquifers, especially those serving facilities such as restaurants that generate a lot of wastewater.

John Teichtler, Door County’s sanitarian, said recent surveys show that about one-third of 6,450 septic systems inspected in his county were classified as failing to work. Teichtler said systems are considered to be failing when they do not meet current standards requiring 3 feet of soil to bedrock, are discharging to the surface or allowing waste to back up into buildings.

Coburn Dukehart / Wisconsin Center for Investigative Journalism

Sampling results in Door County, according to the University of Wisconsin-Extension, show that at any one time in the county, at least one-third of the private wells contain bacteria from animal or human waste.

Ken Bradbury, director of the Wisconsin Geological and Natural History Survey and one of the authors of the Ground Water paper, said he believes the state’s septic laws must be updated to account for the susceptibility of areas such as Door County.

“There is still the perception that just because there is a septic system that meets code, everything is fine,” Bradbury said. “Well, everything is not fine.”

In its 2015 report to the Legislature, the Wisconsin Groundwater Coordinating Council, a multi-agency panel that advises state government on drinking water issues, also issued a stern call for tougher rules for septic systems and well construction in geology marked by fractured bedrock. Current requirements in these areas, the report said, “are inadequate to protect public health and the environment.”

Despite the dangers of contamination from septic systems, Gov. Scott Walker last year proposed eliminating the Wisconsin Fund, which provides money for low-income families to replace failing systems. The fund provided $2.3 million to 500 low-income property owners in 2014-15.

Coburn Dukehart / Wisconsin Center for Investigative Journalism

Officials in Shawano County, which opposed Walker’s proposal, pegged the cost of replacing a septic system at $6,000 to $7,000 for a traditional system and as much as $14,000 for a mound system that provides more protection in areas of fractured bedrock.

In the final budget, the Legislature partially restored the fund but slashed it to $1.6 million this year and $840,000 in 2016-17 — a move criticized by John Hausbeck, who oversees Dane County’s septic program.

“There are homeowners everywhere in the state that do not have the money to replace a septic system,” Hausbeck said. “So they limp along until they end up with water contamination.”

Landspreading under fire

Enforcement of state laws regulating landspreading of septic waste on farm fields also has come under criticism.

In 2015, a citizen watchdog group called the Dunn County Groundwater Guardian Community found 150 sites on which the state DNR allows spreading of septic waste that were below or near the minimum standard for proper soil percolation, or the rate at which water and contaminants move through the soil. Under state law, fields with soil percolation rates greater than 6 inches per hour cannot be used for landspreading.

Neil Koch, a retired hydrologist who organized the citizen group and developed the map of percolation rates, found that 150 of the 400 sites used for spreading septic waste in Dunn County had rates of 5 to 20 inches per hour. Koch said the DNR also recently told him the agency had failed to notify him of an additional 90 landspreading sites in the county.

In a March letter to Koch, Susan Sylvester, director of the DNR’s Water Quality Bureau, acknowledged that the sites he identified did not meet minimal requirements but said reduced application rates were approved because of a low threat to drinking water. Sylvester said lime is added to the waste to kill pathogens, and exposure to sunlight and heat further reduce the risk.

Sylvester added, however, that the agency is reevaluating septage and other landspreading sites throughout Wisconsin. And she noted that compliance checks in Wood County have prompted an increase in septage being hauled to wastewater treatment plants — an option Koch has identified as an “easy solution” to the problem.

Improper application of septic waste in Dunn County, Koch said, “may be the tip of the iceberg.”

Viruses in water also cause illness

Numerous water experts also say the state is failing to protect Wisconsin residents from human and animal viruses in municipal drinking water supplies — some of it tied to leaky municipal sewer systems. Neither federal nor state rules require municipalities to disinfect drinking water drawn from groundwater, which supplies about two-thirds of the state’s potable water, nor are municipalities required to test for viruses.

Jacob Byk / USA TODAY NETWORK - Wisconsin

Viruses are a relative newcomer to the list of pathogens known to endanger drinking water. But the science behind their presence — and their impact on the health of thousands — is already well-documented.

Researcher and microbiologist Mark Borchardt discovered viruses in Wisconsin groundwater in a series of studies while working for Marshfield Clinic. In 2004, for example, Borchardt found that 50 percent of water samples collected from four La Crosse municipal wells tested positive for disease-causing viruses, including enteroviruses, rotavirus, hepatitis A and norovirus.

During 2006 and 2007, Borchardt looked at 14 Wisconsin communities with populations above 1,300 that did not disinfect their municipal water. Tap water was tested, and 621 households were surveyed to determine if viruses were making families sick.

The studies showed that nearly one-quarter of the samples taken from home faucets were swimming with viruses that can cause illness.

Among the 1,079 children and 580 adults surveyed, there were 1,843 cases of acute gastrointestinal illness during the study period. Borchardt attributed 6 to 22 percent of the cases to contaminated drinking water. Researchers also found that up to 63 percent of acute gastrointestinal illnesses among children younger than age 5 were likely caused by norovirus in the drinking water.

Subsequent studies showed the source of the viruses to be leaking municipal sewer pipes, according to a UW-Extension article by Madeline Gotkowitz, a hydrogeologist with the Wisconsin Geological and Natural History Survey.

“Many of these sewers date back to the early 1900s,” wrote Gotkowitz, “and they are cracked and leaky. Inward leakage to these pipes often causes overflows at sewage treatment plants during large rainstorms. However, these pipes also leak raw sewage outward and are common sources of groundwater pollution in urban areas, towns and villages.”

The research illustrates the crucial link between maintenance of infrastructure and water quality. The American Society of Civil Engineers estimated in 2013 that it would cost Wisconsin $7.1 billion to adequately maintain and upgrade drinking water systems over the next 20 years. Municipal wastewater treatment updates and repairs alone would cost about $6.4 billion, the group found.

Several years ago, the city of Adams in Adams County replaced its entire water and sewer system. When workers dug up sections of sewer line, they discovered the old clay pipes had disintegrated, city administrator Bob Ellisor told the Wisconsin State Journal in 2009.

“There were some areas where the sewer didn’t exist anymore,” Ellisor said. “The sewage wasn’t really making it to the sewage plant.”

A “relatively simple” way to ensure the safety of water is to disinfect it, Gotkowitz wrote. Yet, the state does not require such treatment — even in the face of Borchardt’s studies.

In 2009, under Democratic Gov. Jim Doyle, the Natural Resources Board passed a rule requiring disinfection of municipal water by 2013. But in 2011, the Republican-controlled Legislature blocked it on a largely party-line vote. As of February, 56 communities in Wisconsin serving nearly 65,000 people did not treat their water for viruses, according to a report published by Wisconsin Public Radio citing DNR figures.

Among the lawmakers who helped block the rule was then-Rep. Erik Severson, R-Star Prairie, a physician. He told the Milwaukee Journal Sentinel that residents would probably prefer occasional sickness to the cost of upgrading municipal water systems.

Todd Ambs, who was the head of the DNR’s Water Division until 2010, recalls being shocked by the decision. Ambs now heads the nonprofit Healing Our Waters-Great Lakes Coalition, which includes more than 100 groups dedicated to restoring the health of the Great Lakes.

Said Ambs: “That may be, to me, the worst piece of legislation that has gone through the Legislature.”