Nothing puts a damper on the kitchen environment quite like sewage smells emanating from the dishwasher. These foul, rotten egg-like odors are an unfortunately common occurrence that usually result from a number of easy-to-remedy causes. Prevent dishwasher sewage smells by rinsing your dishes free of food before putting them in the washer and keeping your sink drain clean and unclogged with regular vinegar rinses.
In general, sewage-like smells in the dishwasher result from two causes. Most commonly, the odors simply result from the rotten food residue, grease or leftover food particles that build up after numerous wash cycles. Sewage smells also occur when standing water collects in the dishwasher due to drainage issues. Dishwashers commonly connect to sink drains, so stopped-up sinks can cause standing water, which in turn causes rotten odors.
Remedy food-related odors by thoroughly scrubbing the interior of your dishwasher – including the rubber seals, the inside door and the area around the hinges – with a soapy toothbrush. After the scrub down, place 2 cups of white vinegar in dishwasher-safe measuring cups on your washer's bottom rack. Run the machine through a complete washing cycle with no detergent, and then a complete washing cycle with detergent. Use commercial dishwasher and disposer cleaning tablets once per month. Remove dishes before performing cleaning procedures.
Examine the washer's bottom reservoir for large chunks of food or solidified grease buildup, and remove them with paper towels. Wipe any residue or grime from the drain area with a vinegar-soaked paper towel, and remove any foreign objects from the drain. If your dishwasher has a food disposer feature, run the disposer to help unclog the drain. Unclog the kitchen sink using a sink plunger or drain snake. Replace kinked or faulty drainage hoses to remedy sewage smells from standing water.
Plastic smells commonly occur in new dishwashers, as do petroleum- and varnish-like smells, which derive from sound-dampening materials and engine components used in the manufacture of the appliance. These smells should fade naturally after about four to six weeks. Smells that resemble burnt plastic odors can result from washing nondishwasher-safe plastics.