Dishwasher Smells Guide: New Plastic Odor, Burning Smells, and Rotten/Sewage Fixes

Match the smell to the cause before you panic or start scrubbing. A chemical or plastic “new appliance” smell on the first few runs is usually a normal manufacturing newness odor and fades after several detergent cycles (some brands describe a longer break-in). A rotten, fishy, or sewage smell is almost always food in the filter, standing dirty water from a bad drain hookup, or — on a new install — a garbage-disposal knockout plug that was never punched out. A sharp burning smell with no plastic on the heating element is the stop-and-cut-power case.

I’m a homeowner who keeps his own dishwasher running, not an appliance technician or electrician. What follows is checked against manufacturer support pages from GE, Whirlpool, Bosch, Samsung, and LG, plus CPSC recall guidance when burning smells point to a real fire risk. Brand and model details vary — when they do, I say so and point you at your manual.

Key takeaways

• New plastic/chemical smell: Normal for several wash cycles. Run empty (or lightly loaded) cycles with detergent; check for leftover packing film on the heating element before the first dry cycle.
• Burning smell with melted plastic on the element: Power off, cool fully, scrape with a non-metallic tool, then rinse/clean. Put dishwasher-safe plastics on the upper rack only.
• Burning smell with no plastic found, or smoke/sparks: Stop the machine, cut power at the breaker, and get service. Check CPSC recalls for your model.
• Rotten / fishy / sewage smell: Clean the filter first. Then check for standing dirty water, a missing high drain loop or air gap, and — on new installs tied into a disposal — the knockout plug.
• Persistent odor after cleaning and a correct drain setup: Treat it as abnormal and call service or a plumber, depending on whether the problem is the machine or the drain line.

Smell → likely cause → what to do

Smell	Likely cause	First action
Plastic / chemical / “new car” on a brand-new unit	Manufacturing newness odor; tub materials; detergent/rinse aid on first heats	Remove packing materials; run several empty cycles with detergent
Burning plastic during or after dry	Plastic item or packing film on an exposed heating element	Cut power; cool 30+ minutes; scrape residue; plastic on upper rack only (no exposed element: packing check, then service)
Electrical / sharp burning / smoke, no plastic found	Possible heater, wiring, or component failure	Stop; shut off breaker; do not keep running; schedule service; check recalls
Rotten food / fishy / musty	Food in filter, sump, spray arms, or door gasket	Clean filter and interior; run a hot empty clean cycle
Sewage / sewer gas	No high loop/air gap; drain hose too low; backflow from sink/disposal	Inspect drain hose height and connections; fix install; clean disposal
New install that will not drain + foul smell	Disposal knockout plug still in place	Disconnect hose, punch out and retrieve the plug, reconnect

New dishwasher smells (plastic, chemical, “newness”)

A “newness” odor on a brand-new dishwasher is normal. GE Appliances’ odor support page states that manufacturing processes often leave a newness odor that may not dissipate until after several washing cycles, and that you can speed that along by running the dishwasher through several cycles with detergent. GE also notes that during initial use you may smell the tub material, chlorine bleach in detergent, and rinse aid — and that those smells tend to fade with normal use.

That is the honest distinction most people need:

• Normal: Mild plastic, chemical, or “new appliance” smell on early cycles, getting weaker with use (fade time varies by brand).
• Not normal: A smell that does not weaken at all after several detergent cycles, dirty water sitting in the tub between cycles, or a sharp burning smell that is not tied to leftover packaging.

GE is also clear that a dishwasher will not normally retain odors, and that odors present for extended periods should be considered abnormal. So “it’s new, ignore it forever” is not the manufacturer position — run several detergent cycles, watch whether the newness smell is actually fading, and treat standing dirty water or a sharp electrical burn smell as problems now, not later.

Protective film, packing, and first-run checklist

Before you run heated dry for the first time, open the door, pull the lower rack, and look at the tub floor and heating element (on models with an exposed element). GE’s burning-odor guidance specifically says newly installed dishwashers should be checked for packing material on the heating element before use. Film, foam, tape, stickers, and stray plastic bits left from shipping can melt or smell the first time the element gets hot.

Also remove any rack clips, literature packets, or foam blocks that came in the tub. Then:

1. Confirm the filter is seated (many units ship with it installed, but verify it is locked).
2. Run hot water at the sink so the first fill is hot.
3. Run several empty cycles with a normal amount of dishwasher detergent — matching GE’s advice for clearing newness odor.
4. If your model has a sanitize or high-temp option, use it on at least one of those empty runs once you have confirmed there is no packing left on the heater.

How many cycles until it fades? Manufacturers do not publish a universal count. GE’s language is “several washing cycles.” Some brands describe a longer break-in (early plastic/rubber/damping smells that ease over weeks of use). My practical read: if a mild newness smell is clearly weaker after several detergent runs, keep using the machine and keep cleaning/drain checks in mind. If the smell is unchanged after those early detergent cycles, or you have standing dirty water, skip “wait it out” and inspect filter, drain hookup, and packing on the heater. A sharp burning smell is never a wait-it-out case.

When a “new” smell is actually an install problem

Brand-new dishwashers can smell like sewage or rotten water if they cannot drain. That is not a newness odor — it is wastewater sitting in the tub or hose. Two classic new-install mistakes:

1. Garbage disposal knockout plug still in place. When a dishwasher drains into a disposal, the disposal’s dishwasher inlet ships sealed with a plastic plug. Whirlpool’s disposal-connection help and LG installation instructions tell you to knock that plug into the disposer with a hammer and screwdriver, then retrieve it (Whirlpool specifies needle-nose pliers) before clamping the hose on. Leave the plug in and the dishwasher cannot drain properly — dirty water and odor follow quickly.
2. No high drain loop or air gap. GE says dirty water building up between uses is an installation problem from a drain hose installed without a high drain loop or air gap. Whirlpool describes the high loop as the elevated hose section that helps stop sink/disposal wastewater from backing into the dishwasher, and notes a loop height of about 20 inches from the floor (use an air gap if the connection is lower than that, per their guidance). LG warns that if the drain hose is mounted too low, sewer gas smells may come through and sewage water may flow toward the sink connection.

If your brand-new unit smells like a drain instead of a showroom, check the disposal inlet and the hose routing before you buy another bottle of cleaner.

Burning smells (the danger case)

Treat a burning smell as “find the source or shut it down,” not as another cleaning project.

Plastic on the heating element

The most common burning-plastic smell is a plastic utensil, lid, bag scrap, or leftover packing touching an exposed heating element. Both GE and Whirlpool document this. If your model has a hidden heater or condensation/heat-pump dry (no exposed element on the tub floor), skip the scrape steps and treat any unexplained burning smell as a stop-and-service case after a packing/film check.

• Whirlpool: wait until the dishwasher has completely cooled (at least 30 minutes), check around the element for plastic or food, and scrape with a non-metallic tool such as a wooden spoon. Wash only dishwasher-safe plastics, and put those on the upper rack only. After cleanup, a rinse or cleaning cycle helps clear the odor; Whirlpool notes remaining plastic residue can burn off over a few cycles.
• GE: unplug the dishwasher or turn off the house circuit breaker/fuse before maintenance or cleaning. Cool the element before scraping food residue. For melted plastic, GE’s detailed page gives model-specific ways to soften residue briefly with heat, then scrape carefully with a wooden spoon while wearing heat-insulated gloves or oven mitts. If plastic cannot be removed or a burning odor persists, GE says service may be required.

GE also notes that plastic contacting the heater can cause smoke and/or odor, while stating the heater is designed so surface temperature stays well below the ignition temperature of plastic and that this particular melt-on-element scenario was tested against U.S. consensus safety standards. That is reassuring for melted utensil residue — it is not a green light to keep running a machine that smells like wiring, smoke, or burning with nothing on the element.

When to stop and cut power

Do this immediately if any of the following are true:

1. You smell sharp electrical burning, see smoke, or hear popping/arcing.
2. The burning smell continues after you have removed all plastic/packing from the element and run a couple of clean cycles.
3. The smell appears on a machine that has been fine for months or years and then suddenly starts burning without a fallen utensil.

Stop the cycle, shut the dishwasher off, and cut power at the breaker (built-ins are often hardwired). Do not keep restarting it “to see if it clears.” CPSC dishwasher fire-hazard recalls use the same consumer action — stop using the unit and disconnect power. Examples include a 2012 GE/Hotpoint heating-element recall and a 2021 Cove recall that cited consumer reports of burning smells, flames, and smoking. Search your brand and model on cpsc.gov/Recalls while you wait for service.

I am not going to invent a specific failed part from across the kitchen. Heaters, wiring, control boards, and motors can all fail in ways that smell burnt; the homeowner move is power off and a qualified technician, not DIY electrical diagnosis inside a wet appliance.

Rotten, fishy, and sewage smells

These are the everyday dishwasher smells — and they are usually fixable without parts.

Food in the filter and sump

Bosch ties bad dishwasher smells directly to food particles and debris caught in the filter, and tells owners to clean the filter regularly with soap and a soft brush, clear spray-arm holes, and run a dishwasher cleaner on the hottest, longest cycle a few times a year. Whirlpool says food soils that fall into the tub and decompose cause odors, recommends a rinse cycle for partial loads that sit, and offers a vinegar rinse: 2 cups (500 mL) of white vinegar in an upright glass measuring cup on the lower rack, normal cycle, dry option off, no detergent. Samsung links odor problems to grime on filters/nozzles and recommends distilled white vinegar soaks for removable parts, plus an 8-ounce cup of vinegar upright in the lower basket on a Sanitize cycle for interior cleaning (and warns not to use bleach on stainless interiors). LG recommends regular filter cleaning and, for unwanted odors, an empty quick cycle with detergent.

Practical sequence:

1. Pull the lower rack and remove the filter per your manual.
2. Rinse under warm water; scrub with a soft brush — not steel wool.
3. Wipe the sump area under the filter and check spray-arm jets.
4. Wipe the door gasket and the bottom door seal ledge where food collects.
5. Reinstall the filter correctly (a loose filter causes poor wash and more odor).
6. Run a hot empty clean: manufacturer cleaner, or the vinegar method your brand documents.

Standing water and drain-line odor

A little water below the filter can be normal on some designs; a pool of dirty water above the filter line, or water that returns after a drain, is not. Causes worth checking:

• Clogged filter or blocked pump inlet (GE also tells owners to clear debris at the pump inlet).
• Kinked drain hose.
• Missing high loop / air gap (covered above).
• Clogged air gap (the small chrome/plastic dome on some sink decks).
• A full or filthy garbage disposal feeding odor back through the hose.

If the machine drains poorly and smells like sewage even with a clean filter, fix the drain path before blaming the tub.

Cleaning and maintenance that actually prevent smells

• Scrape big scraps before loading. Manufacturers still expect food soil, but bones, labels, and large leftovers belong in the trash, not the filter.
• Clean the filter on a schedule. Monthly is a solid homeowner default; clean sooner if you cook greasy or starchy food often. Bosch, Whirlpool, Samsung, and LG all treat filter cleaning as core odor prevention.
• Do not let a half load sit for days. Whirlpool suggests a rinse cycle for partial loads until you run a full wash.
• Run the machine regularly. GE notes that running at least once a week usually helps prevent mildew odor when food residue is present.
• Crack the door after the cycle if your kitchen stays humid, so the tub can dry — then wipe the gasket if you see slime.
• Use dishwasher detergent, not dish soap. Hand soap oversuds and can leave residue that traps odor.
• Use a rinse aid if your water spots glasses; mineral film can make the tub look or smell dirty even when soil is light.
• Monthly cleaner: brand cleaner (Bosch cleaner, affresh for Whirlpool, citric acid where GE recommends it) on an empty hot cycle beats endless vinegar if you have heavy grease or hard water.

Vinegar methods above come from manufacturer pages, but follow your manual if it limits acid cleaners on certain finishes. Samsung’s stainless warning against bleach is a good example of why brand-specific care matters.

When to call service (or a plumber)

Call appliance service if:

• A burning smell continues after plastic/packing is removed and power-off cooling.
• You smelled smoke, saw scorch marks, or the breaker trips when the dishwasher runs.
• The newness smell has not improved at all after several detergent cycles, filter and drain checks are clean, and the odor is getting stronger rather than weaker — or you also have smoke, standing dirty water, or error codes.
• Error codes for heater, motor, or drain persist after you clear the filter and hose kinks.

Call a plumber or go back to the installer if:

• Dirty water sits in the tub between cycles and the hose has no high loop or air gap.
• A new disposal install still has the knockout plug, or the disposal connection leaks sewage odor into the cabinet.
• Multiple fixtures smell like sewer gas — that can be a house trap/vent issue, not just the dishwasher.

My honest read: start with the smell table, clear packing and the filter, then verify the drain hookup on any new or recently moved unit. Burning without a plastic culprit is where DIY ends and the breaker stays off until someone qualified opens the machine.