What's going on
A septic tank needs time to hold wastewater so solids can settle before the liquid moves on to the drain field. A washer sends a lot of water in a short burst, and several big loads back to back can push water through the tank faster than it was designed for. The EPA's SepticSmart guidance suggests spreading laundry over the week instead of doing it all in one day. Lint matters too. Synthetic fibers don't break down in the tank, and some septic professionals suggest a lint filter on the washer's drain hose.
The washer itself can add water without anyone noticing. An inlet valve that doesn't shut off fully can trickle water into the tub between loads, and some washers sense the rising level and pump it out, so the leak goes straight down the drain. Many rural homes in Onondaga, Madison and Cayuga counties are on both a private well and a septic tank. In those houses, a well pump that kicks on when nobody is using water is often the first clue.
What you can check in five minutes
- Plan laundry as a load or two a day rather than a full day of back-to-back loads.
- With the washer off and the water valves open, look and listen. Water trickling into the tub, or the drain pump running on its own, suggests a leaking inlet valve.
- If you're on a well, notice whether the pump cycles when no taps or toilets are in use.
- Measure detergent by the manual, and use HE detergent in an HE washer. Extra suds help neither the washer nor the tank.
- If you've added a lint filter to the drain hose, clean it often so it doesn't back water up into the washer.
- After laundry, watch for gurgling drains, slow toilets or soggy ground over the drain field. Those point to the septic system, not the washer.
In a house upstate
The septic system is the homeowner's to look after. EPA guidance is to have it inspected by a professional about every three years, and most household tanks are pumped every three to five years, depending on household size and use. If wash water backs up into a floor drain or tub, stop running water and call a septic professional. In some older farmhouses the laundry drain doesn't run where you'd expect, and a septic pro can tell you where yours goes.
What a technician will look at
- •Whether the inlet valve closes fully when the washer is off
- •The water level sensor and fill amount, since an overfilling washer sends more water to the tank
- •The drain pump and any drain or overflow error codes, which vary by model
- •Internal hoses and connections for slow leaks
- •Inlet screens, especially on well water with sediment
Andre's field note: Out in the towns around Syracuse, I sometimes find a washer that has been quietly running water down the drain for weeks because its inlet valve won't close. The owner usually hears the well pump at night before noticing anything else. That's a straightforward washer repair, and the tank gets a break. If orange streaks are showing up on your towels too, read about iron stains from well water.
Washer running when it shouldn't? Call ProFix NYC at (929) 699-8358.