Out of date and poorly constructed septic systems pose a threat to water quality and public health.

A septic system includes a septic tank and a drain field. The tank is designed to provide a place where large solids can settle and be decomposed by microorganisms (scum layer). The drain field removes fine solids and accompanying bacteria (sludge layer). Effluent from a septic tank contains solids, phosphorus, nitrogen, chloride, bacteria, viruses and organic chemicals. For this reason, it is illegal to discharge a septic tank directly into a tile line or other surface water. Non-complying septic systems within Seven Mile Creek Watershed are either tied directly into tile lines, therefore bypassing the treatment phase all together, or leaky, by which poor construction allows untreated wastewater to seep directly into groundwater.

Learn more about a research project that monitored a "straight pipe" septic system before and after installation of a mound system.

Learn more about upgrading a septic system in the Seven Mile Creek watershed - brochure.