About 535,000 homes in Minnesota and another 10,000 businesses rely on septic systems instead of city sewage treatment plants to handle wastewater from toilets, sinks, and showers. According to the Minnesota Pollution Control Agency, at least 30 percent of these home septic systems are either failing to protect groundwater or are an imminent threat to public health and safety because of poor design or poor maintenance.
About 50,000 of these “imminent threats” are so-called straight pipe septic systems, meaning they have no in-ground treatment of the sewage. Rather, the waste is dumped directly into a stream or lake, or into a farm field drain tile pipe which discharges to a water body. Straight pipes have been illegal since the passage of the Clean Water Act in 1972.
Both failing and imminent threat septic systems can cause severe contamination of rivers, lakes, and groundwater.
Minnesota law governs septic systems, but it is carried out by counties and some other local units of government. While it is a homeowner’s and developer’s responsibility to make sure septic systems are properly designed and maintained, many do not pay attention.
Minnesota law requires that if a septic system posing an imminent threat is discovered, it must be fixed within 10 months. However, most county governments do not conduct compliance inspections of septic systems to make sure they are properly maintained and to identify those posing an imminent threat to public health.
In 2003, MCEA developed and helped enact legislation that established and funded a pilot project in several counties, whose officials were to identify and shut down all the straight pipe septic systems in their counties. Four counties ultimately replaced 919 of the 1,103 imminent health threat septic systems found during the inventory; with the rest being replaced as contractors become available and funding becomes available for low-income residents.
The legislation also required the Minnesota Pollution Control Agency to develop a 10-year plan to identify and correct straight pipe septic systems statewide, and established a $25 septic tank fee to raise money for counties to do enforcement and technical assistance.
Despite the plan to eliminate all imminent health threats within ten years, the state has made little progress in removing or fixing them outside the pilot project. MCEA raised the issue in its Petition for Withdrawal or Corrective Action of Minnesota's NPDES Permitting Program. Despite a large estimated reduction in imminent health threats in 2009, very few straight pipes were reported to the state.
2010 local government SSTS report data
2003 MCEA presentation on SSTS
Photos of SSTS in MN
Minnesota Law governing septic systems
2009 Dedelegation petition
MPCA reports on SSTS
MCEA SSTS fact sheet
MCEA 2012 comments to the Clean Water Council on SSTS
MPCA SSTS website