What should you do when a septic tank backs up?
Last updated July 10, 2026
Short answer
Stop all water use in the home immediately, avoid contact with any backed-up wastewater, and call a licensed septic professional right away. Do not attempt to pump or open the tank yourself. If sewage has entered the home, treat the affected area as contaminated until cleaned professionally.
A backup means the system can no longer accept water, so continuing to run water, flush toilets, or run a dishwasher or washing machine will make the problem worse and can push more sewage back into the home. Wastewater backup carries real health risks, so avoid direct contact and keep children and pets away from the affected area. While waiting for a professional, note when the backup started and whether it happens with every fixture or just one, since that detail helps the technician diagnose the problem faster. This is one of the few septic issues that qualifies as a true emergency and shouldn't wait until regular business hours.