Septic Smell in Dishwasher

Appliance Maintenance

• A properly installed and maintained dishwasher shouldn't have issues with bad smells, unless you leave dirty dishes in the appliance for days before running a wash cycle. Hard-water salts may build up in the water pump or drainage hoses. Caked-on food is dissolved in soapy water and then removed through the water pump, drainage hose and into the kitchen's sink drain pipes under the counter. If any part of the waste-expulsion system is clogged or contains a mass of wet, decaying food particles, a very bad odor can arise from within the dishwasher.

Initial Troubleshooting

• Modify your use of the dishwasher. Run full loads every two days, which helps keep the water pump, hoses and sink drainage system more regularly flushed with water. Increasing the use may push out any remnant food particles from the dishwasher system, avoiding the stench of rotten meat, fats or vegetables. Cleanse the dishwasher by running it empty, but with a gallon of white vinegar poured into the bottom basin. Alternatively, a citric acid powder may be used to help remove any buildup of hard-water salts and flush the drains clean.

Persistent Smells

• After changing your scheduled use of the dishwasher and cleaning with vinegar, the septic smell may remain. Next thoroughly examine the basin of the dishwasher, looking for signs of food debris. Also pull out the dishwasher from the cabinet skirt to ensure the drainage hose isn't kinked or constricted. Unplug the dishwasher if you choose to prod around the water pump or disassemble it in any way looking for sludge or food waste. Follow the hose all the way to the main kitchen sink drain pipes. If the dishwasher drainage hose empties into the food disposal, rotting food debris may be collecting there. Remove the drain plug from atop the disposal in the sink and smell the canister. Food and other gunk may deposit there after the dishwasher runs. Run the disposal with water and vinegar to cleanse it.

Bigger Issues

• If examining the drainage hoses, under-counter disposal unit and the main sink plumbing doesn't correct the septic smell from the dishwasher, contact a professional plumber to investigate. If septic gas is truly invading your plumbing pipes, a more serious situation may exist. A buildup of septic gas may be indicative of a poorly working system or blocked air-intake vents. These bad situations cause unusual gases and odors to proliferate and move through the vacant spaces of all house plumbing. Methane gas, for example, may be toxic in large amounts and it is flammable.