Public health sanitarian Regina Young wasn’t sure what her staff would encounter when the Barry-Eaton District Health Department clamped down on failed septic systems in 2007.
They quickly discovered more problems than anyone anticipated in those two largely rural counties, said Young, supervisor of the Barry-Eaton District Health Department’s Water Protection Team.
In the first six years of the program, Young’s staff discovered nearly 1,000 failed septic systems and 300 houses with no septic systems whatsoever. In those cases, household sewage was piped into the nearest farm drain, lake or stream.
“The ways that people come up with to get rid of their sewage just blows your mind,” Young said. “It’s hard to think of a worst case example … there were so many.”
By catching and correcting failed septic systems and illicit sewage discharges over the past six years, Young said health officials kept 107 million gallons of raw sewage from reaching surface waters and groundwater in the two counties between Lansing and Holland.
Problems extend statewide
There are about 1.3 million on-site wastewater treatment systems in Michigan, most of which are septic systems for single-family homes. State officials estimate that 10 percent of those (130,000) have failed and are polluting the environment.
But the problem may be far worse. Several counties that require septic tank inspections during real estate transactions have reported a septic system failure rate of 20 percent to 25 percent, according to a Michigan Department of Environmental Quality report.
Failed septic systems are a concern because human sewage is loaded with pathogens that can threaten the health of people who swim in polluted waters or drink contaminated well water. Several experts interviewed by Bridge said water pollution from failed septic systems is a serious, but under-appreciated, problem across Michigan.
“We’ve tested rivers in the Lower Peninsula during low flow conditions (when most of the river water is groundwater, not runoff from the landscape) and we can detect signs of septic tank waste,” Rose said. “The more sewage tanks that are in the area, the higher the human sewage markers in the water.”
Among the rivers studied, MSU scientists found the highest levels of genetic markers, indicating the presence of human fecal matter, in the South Branch of the Black River in Southwest Michigan, Bear Creek, the Kalamazoo River, the Huron River and the Pere Marquette. Rose said there was no doubt that the fecal matter in those rivers came from leaky septic systems.
Human waste has to go somewhere
Each day, Michigan residents discharge about 264 million gallons of wastewater into septic systems and other on-site treatment facilities. About 10 percent of that wastewater is piped into failed on-site treatment systems, according to state data.
Over the course of a year, that amounts to 9.4 billion gallons of untreated wastewater flowing into failed treatment systems, DEQ estimates.
Some of that raw sewage — no one knows how much — ends up in lakes, streams and underground aquifers that supply drinking water wells.
Septic systems and other on-site wastewater treatment systems for homes and businesses work well when properly installed and maintained. The problem is that many homeowners fail to maintain septic systems because it’s not required.
Michigan is the only state without a statewide code governing how septic systems are designed, installed and maintained. County health departments regulate where septic tanks can be installed, but just 11 of Michigan’s 83 counties have programs that identify failed septic systems and force repairs.
The result is a patchwork of regulations and scores of failed septic systems that go undetected, said Richard A. Falardeau, chief of DEQ’s environmental health section.
Septics go suburban
Septic systems were originally designed for rural areas, where homes often were too far away to connect to a centralized, municipal wastewater treatment system. Now the devices are a popular method of sewage disposal in many suburban communities.
The growth of suburbs over the past 50 years did more than transform the landscape: Urban sprawl also fueled a dramatic increase in the number of septic systems.
In 1990, 28 percent of single-family homes in Michigan were connected to septic systems, according to state data. By 2004, 50 percent of all new homes were using septic systems to handle household wastewater.
Local health departments issue more than 30,000 permits each year for new and replacement septic systems in Michigan.
“Back in the day we had dense communities and farms were the only places that had septic tanks. Along come interstates and urban sprawl and now you have septic systems being used in a completely different manner than they were born into,” said Jim Hegarty, a civil engineer and expert on wastewater treatment systems.
Nationally, 26 million homes and 60 million people use septic tanks or other on-site sewage treatment systems. The majority of those devices work as designed, but many states have reported septic system failure rates that rival Michigan’s.
One of the worst cases of a failed septic system contaminating well water occurred in Door County, Wis., in 2007. More than 200 customers at a restaurant and six employees suffered intestinal ailments after drinking contaminated water.
Septics vs. sewers
Larry Stephens, an engineer and president of the Michigan On-site Wastewater Recycling Association, said septic systems and other on-site wastewater treatment systems get a bum rap. He said small, decentralized treatment systems are more environmentally friendly than large municipal wastewater treatment facilities that serve entire communities.
“A properly maintained on-site treatment system is more sustainable than the centralized treatment systems,” said Stephens, whose consulting firm oversees construction of on-site systems.
He said municipal sewer systems dump more untreated sewage into lakes and rivers than all the septic systems in Michigan combined. State data support his claim.
According to DEQ data, Michigan’s municipal wastewater treatment facilities discharged 7.8 billion gallons of raw sewage and another 21.6 billion gallons of partially treated sewage into lakes and rivers in 2011. Most of those discharges occurred in Detroit and other cities where heavy rainfall overwhelmed combined sewer systems that treat both wastewater and stormwater. (Coming May 16: When rains and sewage combine.)
“Wastewater treatment plants are supposed to fix their combined sewer overflows, but anytime untreated sewage enters the environment it is a risk,” Rose said. “Septic tanks are a known risk contributing viruses to groundwater and surface water. They have been linked to (disease) outbreaks … so we cannot ignore this.”
Jeff Alexander is owner of J. Alexander Communications LLC and the author of "Pandora's Locks: The Opening of the Great Lakes - St. Lawrence Seaway." A former staff writer for the Muskegon Chronicle, Alexander writes a blog on the Great Lakes.
Hydrogeology Group, Geological Sciences Department, Michigan State University