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How to clean a dishwasher: remove and scrub the filter, clear the spray-arm holes with a toothpick, wipe the door seals and detergent dispenser, then run an empty hot cycle with 2 cups of white vinegar on the top rack followed by a short hot cycle with 1 cup of baking soda on the bottom. Clean the exterior and check the drain. The full deep clean takes about an hour, most of it hands-off, and fixes smells, cloudy glasses, and poor cleaning performance.
This guide is research-based, compiled from manufacturer care instructions (Bosch, Miele, Samsung, LG, Whirlpool, GE) and widely published appliance-maintenance guidance. Below: why dishwashers get dirty despite “washing themselves,” the complete deep-clean step by step, filter and spray-arm care, descaling for hard water, fixing standing water and odors, what never to do, troubleshooting, and an FAQ.
The Paradox: Why a Dishwasher Needs Washing
It seems absurd — the machine that cleans your dishes needs cleaning itself. But a dishwasher doesn’t wash itself; it recirculates the same water through filters and spray arms, and everything it strips off your dishes has to go somewhere. Grease coats the filter and the sump. Food particles lodge in spray-arm holes. Detergent residue and hard-water minerals film the interior walls. Soap scum and mildew colonize the door seals, which never get fully hot or fully dry.
The symptoms of a dirty dishwasher are unmistakable once you know them: glasses come out cloudy or spotty, there’s a musty or rotten-egg smell when you open the door, the bottom of the tub feels slimy, water pools in the filter well after a cycle, or dishes simply aren’t getting clean despite fresh detergent. Most “my dishwasher is dying” service calls are actually “my dishwasher has never been cleaned” — a deep clean restores performance dramatically in the majority of cases.
There’s also an efficiency angle: a clogged filter forces the pump to work harder, a scaled heating element uses more energy per cycle, and blocked spray arms mean rewashing dishes — tripling the water and energy cost of every load. Monthly maintenance keeps the machine cleaning well and running efficiently.
What You’ll Need
- White distilled vinegar (2 cups) and baking soda (1 cup)
- An old toothbrush and toothpicks or a thin wire
- Microfiber cloths and a sponge
- Rubber gloves (the filter is unpleasant)
- Optional: citric-acid powder food-grade citric acid Check Price on Amazon → for heavy hard-water scale, or a dishwasher cleaner product dishwasher cleaner tablets Check Price on Amazon →
How to Clean a Dishwasher: Step-by-Step Deep Clean
Step 1: Empty it and remove the racks
Start with an empty dishwasher. Pull out the bottom rack (and the top rack if it lifts out easily on your model) to access the filter and spray arms. This also lets you inspect the racks — check for rust spots on the tines where the vinyl coating has chipped, which can stain dishes and snag. Set the racks aside.
Step 2: Remove and scrub the filter
The filter — usually a cylindrical assembly in the floor of the tub that twists out counterclockwise — is the heart of dishwasher maintenance. Pull it out (consult your manual for the exact mechanism; some have a coarse flat filter plus a fine cylindrical one). You’ll likely find a sludge of grease and trapped food. Disassemble its parts and scrub every surface with hot soapy water and the toothbrush, including the mesh. Rinse thoroughly. A clean filter is the single biggest factor in dishwasher performance — manufacturers like Bosch recommend cleaning it weekly for heavy users, monthly at minimum. While the filter is out, wipe the sump area beneath it and remove any debris (bones, glass shards, twist ties) with gloved hands.
Step 3: Clear the spray arms
Unclip or unscrew the lower and upper spray arms (most lift or twist off without tools). Hold each up to the light and check every jet hole — clogged holes are the direct cause of dishes coming out dirty in patterns. Clear blockages with a toothpick or thin wire, then rinse the arms under hot water, shaking them to dislodge internal debris. Spin each arm by hand before reinstalling; they should rotate freely. If an arm is cracked or a jet is permanently damaged, replacements are inexpensive and model-specific.
Step 4: Wipe the seals, dispenser, and door edges
The rubber door gasket — running around the tub opening — is a mildew haven because it stays damp and never gets hot. Wipe the entire gasket with hot soapy water, using the toothbrush in the folds. Clean the detergent dispenser cup and rinse-aid cap (dried detergent cakes in both), the door’s inner bottom edge where grime collects below the gasket line, and the control panel with a barely-damp cloth. For mold spots on the gasket, wipe with white vinegar and let it sit 10 minutes before wiping clean.
Step 5: The vinegar cycle
Reinstall the filter, spray arms, and racks. Place a dishwasher-safe bowl or measuring cup with 2 cups of white distilled vinegar on the top rack. Run an empty cycle on the hottest setting (sanitize or heavy cycle if available) with no detergent. The hot vinegar dissolves grease films, soap scum, and light mineral scale throughout the tub, pump, and spray system. Your kitchen will smell like vinegar during the cycle — that’s normal and dissipates.
Step 6: The baking-soda cycle
After the vinegar cycle finishes, sprinkle 1 cup of baking soda across the bottom of the tub and run a short hot cycle (no detergent). The baking soda deodorizes and brightens the stainless interior. Some people combine vinegar and baking soda in one cycle — don’t; they neutralize each other and you lose both benefits. Sequential cycles are the correct method.
Step 7: Descale if you have hard water
If your area has hard water (white film on the tub walls, cloudy glasses despite rinse aid), the vinegar cycle may not be enough. Instead of — or after — the vinegar step, run an empty hot cycle with 2–3 tablespoons of citric-acid powder in the detergent cup, or use a commercial dishwasher cleaner per its label. Citric acid is the heavy artillery for mineral scale and is explicitly recommended by Miele and Bosch for hard-water maintenance. Repeat quarterly in hard-water areas.
Step 8: Exterior and final checks
Wipe the exterior door and handle with a damp cloth (stainless: wipe with the grain). Check that the drain hose under the sink isn’t kinked. Leave the door ajar for an hour after the cleaning cycles so the interior dries fully — this one habit, done after every wash cycle, prevents most odor problems permanently.
Fixing Standing Water in the Bottom
A little water in the filter well after a cycle is normal — most dishwashers leave some in the sump by design. Standing water covering the tub floor is not. Work through this sequence: 1. Clean the filter (the cause most of the time). 2. Check the drain hose for kinks and the garbage-disposal knockout plug — if the dishwasher drains through a new disposal, the knockout plug inside the disposal’s dishwasher inlet must be removed or water can’t drain at all. 3. Clear the air gap (the small cylinder on the sink deck) of debris. 4. Run the disposal to clear its drain path. If water still stands after all four, the drain pump or check valve likely needs service — that’s a repair call, not a cleaning issue.
Preventing Odors Permanently
Dishwasher odor has three root causes, all preventable: food rotting in the filter (solved by regular filter cleaning), the door sealed shut between cycles (solved by leaving it ajar to dry — the single most effective odor prevention), and low-temperature eco cycles that don’t fully dissolve grease (run a hot cycle weekly if you normally use eco mode). Scrape — don’t rinse — dishes before loading: modern detergents need some food soil to work properly, but chunks of food belong in the trash, not the filter. And run the dishwasher regularly; a machine that sits unused for weeks grows biofilm in the sump.
What Never to Do
1. Never use bleach in a dishwasher with a stainless-steel interior — it pits the steel; it’s also unnecessary given vinegar and citric acid. 2. Never put dish soap (hand-washing liquid) in the dispenser — it creates a foam flood that can damage the pump and flood the kitchen. 3. Never run the vinegar bowl on the bottom rack where it can tip and spill concentrated vinegar on the heating element. 4. Never ignore a damaged door gasket — if it’s torn or permanently moldy, replace it; cleaning can’t fix a failed seal. 5. Never use abrasive pads on the stainless tub — they scratch the finish and give grime new footholds.
Maintenance Schedule
| Frequency | Task |
|---|---|
| After every cycle | Leave door ajar to dry; scrape (don’t rinse) dishes before loading |
| Weekly–monthly | Remove and scrub the filter (weekly for heavy use, monthly minimum) |
| Monthly | Vinegar + baking-soda cleaning cycles; wipe seals and dispenser |
| Quarterly | Clear spray-arm holes; descale with citric acid (hard water); inspect racks and gasket |
Troubleshooting
Cloudy glasses after cleaning: if the vinegar/citric cycles didn’t fix it, the cloudiness may be permanent etching from soft water + too much detergent — try less detergent and check your water softener setting. Detergent pod not dissolving: usually a blocked dispenser door or water too cool — clean the dispenser and run hotter cycles; also don’t nest the pod under large items. Dishes wet after cycle: use rinse aid (it dramatically improves drying, especially on plastics), and unload the bottom rack first so water pooled on top-rack items doesn’t drip down. Garbage-disposal-like smell: the drain hose may lack a proper high loop, letting sink water backflow — check the hose routing. Rust spots on dishes: chipped rack coating — touch up with rack-repair paint or replace the rack.
Frequently Asked Questions
How often should I clean my dishwasher filter?
Monthly at minimum; weekly if you cook daily and run full loads. The filter traps everything the spray arms strip off your dishes, and a clogged filter is the number one cause of poor cleaning performance and odors. It takes two minutes: twist out, scrub with hot soapy water and a brush, rinse, and reinstall. Bosch and other manufacturers explicitly recommend this frequency in their manuals.
Can I use vinegar in my dishwasher?
Yes — 2 cups of white distilled vinegar in a bowl on the top rack, run empty on hot, is the standard manufacturer-endorsed cleaning method. The long-standing concern about vinegar damaging rubber seals is overstated for occasional monthly use; the far greater risk to seals is never cleaning at all. Don’t pour vinegar directly on the heating element or use it every single cycle — monthly is the right cadence.
Why does my dishwasher smell bad?
Almost always one of three things: a dirty filter with rotting food, the door kept sealed shut between cycles (trapping moisture), or grease buildup from constant low-temperature eco cycles. Deep-clean per this guide, then leave the door ajar after every cycle — that single habit prevents most odor recurrence permanently.
Should I rinse dishes before putting them in the dishwasher?
Scrape, don’t rinse. Modern enzyme detergents are designed to attach to food soil — pre-rinsed dishes can actually come out less clean, and you’re wasting water. What you must remove: bones, large chunks, and anything that will clog the filter. Everything else, let the machine and detergent handle.
What causes white film on dishes and the tub?
Hard-water mineral scale, in most cases — run the citric-acid descale cycle described above and consider rinse aid. If the film persists only on glasses and wipes off with vinegar, it’s scale. If it’s permanent cloudiness that vinegar won’t touch, it’s etching (common with soft water and excess detergent) — reduce detergent and check softener settings.
Is standing water in the bottom of the dishwasher normal?
A small amount in the filter well/sump is normal by design. Water covering the tub floor is not — work through the sequence in the standing-water section: clean the filter, check the drain hose and disposal knockout plug, clear the air gap, and run the disposal. Persistent standing water after all that indicates a pump or valve problem needing service.
