When you flush, where does the water go?

When the Minneapolis first began pumping drinking water from the Mississippi River in 1871 and 1885, many people got sick from drinking untreated water.
When the Minneapolis first began pumping drinking water from the Mississippi River in 1871 and 1885, many people got sick from drinking untreated water.

When Minneapolis first began to pump drinking water from the Mississippi River in 1871 and 1885, the river was a dumping ground for human sewage, garbage, and carcasses from the local slaughterhouses. For nearly thirty years, people continued to drink contaminated river water, resulting in outbreaks of typhoid and cholera that killed hundreds every year. Eventually, in 1910, Minneapolis started treating its drinking water with chlorine and within a year, both diseases were virtually eliminated. St. Paul followed suit, although not until 1920! Much, much later, in 1938, the Twin Cities built their first wastewater treatment plant and finally began cleaning up the sewage from homes and business instead of dumping it straight into the river.

Today, the Metropolitan Council operates eight wastewater treatment plants in the seven county metro area. Homes in Stillwater, Oak Park Heights and Bayport connect to the St. Croix Valley Treatment Plant, which sits on the St. Croix River in Oak Park Heights. Homes in Cottage Grove and southern Woodbury connect to Eagles Point Treatment Plant, on the Mississippi River in Cottage Grove. The Metro Plant in St. Paul is by far the largest and provides treatment for more than 60 cities, including Minneapolis and St. Paul, as well as dozens of east metro communities.  In unsewered areas however, however, most homes have their own subsurface sewage treatment systems (SSTS), which are more commonly referred to as septic systems.  These systems are designed to safely treat household wastewater, capturing oils and sludges, breaking down bacteria and pathogens, and allowing the water to filter gradually into the ground through soils and rock. Sometimes, however, older systems break down and begin to leak, or systems are installed improperly without enough soil on top of the bedrock to filter out bacteria and contaminants before the wastewater flows into shallow groundwater aquifers and nearby streams.

Across Minnesota, 533 streams and river reaches have unsafe levels of E. coli or fecal coliform, which are bacteria found in human and animal feces. In Washington County, water monitoring has found nine streams with elevated levels of E. coli. These streams include Brown’s Creek (Grant/Stillwater); Trout Brook and Kelle’s Creek (Afton); Perro Creek (Bayport); Gilbertson Creek (Scandia); Swedish Flag (Copas); and three unnamed streams (one running from Boutwell Rd to Brown’s Creek Preserve in Stillwater, one flowing into Big Carnelian Lake in May Twp., and one connecting Bone Lake in Scandia to Birch Lake in Chisago County). For some of these streams, manure-laden runoff from nearby farms could be a source of E. coli, but in many cases, the primary source is suspected to be failing septic systems.

Surface and groundwater interact.
Surface and groundwater interact.

For several years, the Valley Branch Watershed District has been working with the Minnesota Pollution Control Agency to determine how E. coli is getting into Kelle’s Creek, a small, groundwater-fed stream in Afton, which is surrounded by mostly undeveloped land. The stream is home to an unusually large number of macroinvertebrate species (insects and other water critters), which is an indication of very good water quality and a healthy, intact biological web. However, studies estimate that 25% of the private septic systems in the Kelle’s Creek watershed are failing to treat wastewater before it enters shallow groundwater aquifers. The contaminated groundwater is then flowing into Kelle’s Creek, which enters the St. Croix River at the south end of downtown Afton.

Groundwater is particularly at risk in the southern and eastern portions of Washington County because of something known as karst topography. The bedrock in this area is mostly limestone, which is easily dissolved by water. As a result, pollution can easily travel down into aquifers through cracks and holes that have formed in the bedrock over time.

Last year, the Valley Branch Watershed District received a Minnesota Clean Water Grant to help address the E. coli problem in Kelle’s Creek. They are currently offering free septic inspections to all homeowners within the Kelle’s Creek watershed (normally $400-500) in order to identify failing systems. The Watershed District has also created a fund to help cover 25% of the cost (up to $5000) for homeowners to replace their systems if they are found to be failing and ordered to be replaced.

Elsewhere in Washington County, the Department of Public Health and Environment has financial assistance available to help people replace failing septic systems. There are low-interest loans, with interest rates of 1.5–3%, open to all landowners, as well as partial grants for low-income households.  To qualify for this assistance, septic systems must be deemed noncompliant by the county or a private inspector and ordered to be replaced. (The county cannot fund completed or underway projects.) In addition, the county requires that all septic tanks be pumped every 3 years and all systems be inspected during home sales and before the issuance of a building permit for a home addition that will create new bedrooms.

If you live within the Kelle’s Creek watershed in Afton contact Jennifer Koehler to learn more about the special grants for septic inspections and replacement: 952-832-2750 or jkoehler@barr.com. More info about the project at www.vbwd.org/KellesCreek.html.

If you live elsewhere in Washington County, contact the Department of Public Health and Environment to learn more about permits and inspections for septic systems and financial assistance for septic replacement: 651-430-6655 or PHE@co.washington.mn.us.