Signs your septic system is failing

EPA lists these as common signs of a failing septic system:¹

• Water and sewage from toilets, drains and sinks backing up into the house
• Bathtubs, showers and sinks draining very slowly
• Gurgling sounds in the plumbing
• Standing water or damp spots near or over the septic tank or drain field
• Sewage smells around the tank or drain field
• Bright green, spongy, lush grass over the tank or drain field, even in dry weather
• Algae blooms in nearby lakes or ponds
• High levels of nitrates or coliform bacteria in a drinking water well

The University of Minnesota's septic program adds two more: an alarm sounding, and frozen pipes or a frozen drain field.²

Not every smell means a failure: EPA says an odor can come from a roof vent or other vent pipe, which is a normal part of the system, though a vent can clog with leaves or freeze in a long cold spell.¹

• Stay out of it. EPA says to avoid contact with sewage that's backed up into the house, as it can carry germs, and to ask your local health department for guidance.¹
• Clean up safely. EPA says anyone cleaning up should wear protective clothing such as long rubber gloves and a face shield, disinfect everything the sewage touched with a mix of 90 percent water and 10 percent household bleach, and leave the area unused until it's been completely dry for at least 24 hours.¹
• Call a septic company. EPA's advice is to contact a local septic service provider, your local health department or the state's onsite wastewater agency.¹
• Never go into the tank. The gases in a septic tank can kill you.³

For a backup or overflow, the request form lists septic companies near you to call.

On a mound system, the alarm sounds when the liquid in the pump chamber gets too high. That can be a faulty pump, float or circuit, or too much water use. Using less water (no baths, showers or laundry) while you get it fixed lets the chamber's reserve space buy you time.⁴

Before you call, the Washington State Department of Health suggests checking for a tripped breaker or blown fuse and an unplugged pump or float cord. Don't go into the pump chamber, and turn the power off at the breaker before touching the pump or floats. If that doesn't find it, call for service: repairs to pumps and other electrical parts have to be done by a licensed professional.⁴

EPA says most septic systems fail because of a poor design or poor maintenance, and that some drain fields are put in soil that isn't suitable, on steep slopes or over high groundwater.¹ The University of Minnesota's program adds using too much water, as when a house of one or two people is sold to a family of five or six and water use jumps.²

When a tank isn't pumped, solids can build up and flow out into the drain field and clog it.¹ By the time sewage backs up into the house, Penn State Extension says, the drain field is usually clogged and flooded, and pumping the tank won't clear it.⁵

• Inspect and pump on schedule. EPA says to have the system inspected every 1 to 3 years and the tank pumped every 3 to 5 years.¹ The pumping guide covers what sets your interval.
• Flush only toilet paper and human waste. EPA's list of things never to flush includes cooking grease, non-flushable wipes such as baby wipes, diapers, paper towels, cat litter, medicines and household chemicals.⁶
• Spread out the laundry. Doing all the washing on one day doesn't give the tank time to treat the waste and can flood the drain field.⁶
• Keep off the drain field. Don't park or drive on it, keep roof drains and sump pumps away from it, and plant trees far enough away that roots can't reach the system.⁶
• Skip the additives. EPA says additives aren't needed for a system treating household wastewater, and some can harm it.⁷

What fixing a problem costs depends on the part. The repair cost guide has the published ranges.