Septic System Anatomy
Effluent Filter
An effluent filter is a cartridge-type filtering device installed in the outlet baffle of a septic tank that provides an additional barrier against solids reaching the drainfield. The filter allows liquid effluent to pass through while capturing small suspended solids and particles that would otherwise exit with the liquid. Modern Minnesota septic systems installed after 1996 are typically required to have effluent filters; many older systems have had them retrofitted.
Effluent filters require periodic cleaning — typically every 2–3 years, often performed during the same visit as tank pumping. A clogged effluent filter will cause wastewater to back up in the tank and eventually back up into the house if not cleaned. While this backup is an inconvenience, it is far preferable to the filter doing its job and keeping solids out of the drainfield.
What This Means for You
If your system has an effluent filter, make sure it is cleaned every time the tank is pumped. A filter that is never cleaned will eventually clog and cause household drain backup — a messy problem that is entirely preventable with routine maintenance. Ask your service technician to inspect and clean the filter at every pumping visit.