How to Clean Your Dishwasher (Yes, It Needs Cleaning Too)

There's a certain irony to a dirty dishwasher. The machine designed to clean your plates, glasses and cutlery can itself become a source of odour, bacteria and residue — and most people never clean it at all.

If your dishwasher smells musty when you open it, if your glasses come out with a white film, if the interior looks greasy or discoloured, or if you've simply never cleaned it and can't remember when you last did — this post is for you.

A dishwasher that isn't maintained becomes progressively less effective over time. Food debris accumulates in the filter. Limescale builds up on the spray arms, blocking the jets. Grease coats the interior walls. Mould grows in the door seal. None of these things are obvious from the outside, but they all affect the cleanliness of your dishes and the hygiene of your kitchen.

---

Why Dishwashers Get Dirty

Understanding why the machine gets dirty helps you know what to target.

Food debris: Every load puts food particles into the machine. The filter at the base catches most of it, but fine particles accumulate on the spray arms, the interior walls and the door edges. Over time this becomes a biofilm — a sticky layer of organic matter that smells and harbours bacteria.

Grease: Cooking grease on dishes goes into the dishwasher water and some of it coats the interior walls and the door seal rather than draining away. This creates a greasy film that traps more food debris and becomes progressively worse.

Limescale: Adelaide's hard water leaves calcium deposits on every surface the water touches. In a dishwasher, this manifests as white scale on the spray arms, the interior walls, the heating element and the filter housing. Limescale on spray arms blocks jets and reduces cleaning effectiveness. Limescale on the heating element makes it less efficient and can eventually cause it to fail.

Mould: The door seal (the rubber gasket around the door) stays damp between cycles and in a warm kitchen creates ideal conditions for mould. Black or grey mould in the door seal is extremely common and is a frequent source of musty dishwasher smell.

---

How Often Should You Clean Your Dishwasher?

Filter: Clean monthly. This is the most important maintenance task and the one most frequently skipped.

Door seal: Wipe weekly during your regular kitchen clean. Inspect for mould monthly.

Interior walls and spray arms: Clean monthly alongside the filter.

full deep clean in Adelaide with descaler: Every 3 months, or more frequently if you have hard water or notice limescale buildup.

If you've never cleaned your dishwasher and it's been in regular use for more than a year, start with a full deep clean before moving to a maintenance schedule.

---

Step 1: Clean the Filter (This Is the Priority)

The filter is the single most important component to clean. Most people don't know it exists. It sits at the base of the dishwasher interior, usually in the centre or at the back, and it catches food debris from the wash water to prevent it from recirculating onto dishes.

A clogged filter means dirty water recirculates through your machine. This is why dishes sometimes come out with a fine gritty residue or a greasy film even after a full cycle.

To clean the filter:

1. Remove the bottom rack and set it aside.

2. Locate the filter — it's usually a cylindrical piece that twists out of a housing, sometimes with a flat mesh filter beneath it. Check your dishwasher manual if you're not sure how to remove it.

3. Take the filter to the sink and rinse it under warm running water to remove loose debris.

4. Use a soft brush (an old toothbrush is ideal) with dish soap to scrub the mesh. Food debris can pack into the mesh tightly and won't rinse out without brushing.

5. Rinse thoroughly and replace. Make sure it clicks or locks back into place — a loose filter lets debris bypass it.

If the filter has a strong odour, soak it in a bowl of warm water with a few tablespoons of white vinegar for 15 minutes before scrubbing.

---

Step 2: Clean the Door Seal

The rubber gasket around the inside of the door is a prime location for mould, food debris and odour. It has folds and crevices that trap moisture and stay damp indefinitely.

1. Open the door fully.

2. Use a damp microfibre cloth or an old toothbrush with a small amount of dish soap or white vinegar to clean along the entire length of the seal. Get into every fold and crevice — mould hides in the folds.

3. For visible black mould, apply a diluted bleach solution (1 part bleach to 10 parts water) to the affected area, leave for 5 minutes, then scrub and wipe clean. Rinse with a damp cloth to remove bleach residue.

4. Dry the seal with a clean cloth after cleaning — leaving it damp encourages mould to return.

The bottom edge of the door, where the door meets the tub when closed, also accumulates significant debris. Wipe this area thoroughly — it's often overlooked.

---

Step 3: Clean the Spray Arms

The spray arms have small jets that distribute water throughout the machine. In hard water areas like Adelaide, these jets can become partially or fully blocked with limescale, and food debris can also clog them.

Blocked jets mean uneven water distribution and dishes that don't get clean.

1. Remove the spray arms — they usually unclip or unscrew from their mounting point. Check your manual if needed.

2. Rinse under running water and use a toothpick or cocktail stick to clear any blocked jet holes. You can see the jets on the underside of each arm — check each one.

3. For limescale blocking the jets, soak the spray arms in white vinegar for 20–30 minutes. The acid dissolves calcium deposits and the jets clear easily with a toothpick after soaking.

4. Rinse thoroughly and replace.

---

Step 4: Wipe the Interior Walls and Edges

The interior walls, the door interior, and the edges and crevices around the door accumulate grease and grime that a dishwasher cycle doesn't clean because the water jets aren't aimed at these surfaces directly.

1. Use a damp microfibre cloth with a small amount of dish soap or white vinegar to wipe all interior surfaces — walls, ceiling, door interior.

2. Pay particular attention to the bottom edges where the door meets the tub, the corners, and any plastic components that have visible grime.

3. Wipe the cutlery basket and any removable rack components.

---

Step 5: Run a Cleaning Cycle — Vinegar Method

Once you've done the manual cleaning above, run an empty hot cycle to flush and deodorise the machine.

Vinegar cycle:

1. Place a dishwasher-safe bowl or cup filled with 250ml of white vinegar on the top rack.

2. Run the hottest, longest cycle available — do not add detergent.

3. The vinegar disperses through the machine, dissolving limescale residue, cutting through grease film and deodorising the interior.

This is safe for most dishwashers. White vinegar will not damage rubber seals or stainless steel interiors when used at this dilution.

---

Step 6: Run a Second Cycle — Baking Soda Method

After the vinegar cycle:

1. Sprinkle a cup of baking soda across the base of the dishwasher.

2. Run a short hot cycle.

3. The baking soda deodorises and provides a mild abrasive action that brightens the interior.

The combination of the vinegar cycle and the baking soda cycle leaves most dishwashers noticeably cleaner-smelling and looking.

---

Step 7: Use a Commercial Dishwasher Cleaner Quarterly

For a quarterly deep clean, a commercial dishwasher cleaner (Finish Dishwasher Cleaner is widely available and well-reviewed) provides a more thorough descaling and degreasing action than the vinegar method alone. Follow the product instructions — typically placed upright in the bottom rack and run on a hot empty cycle.

If you have significant limescale buildup, a dedicated dishwasher descaler (available at hardware stores) is more aggressive than a standard cleaner and more effective for heavy mineral deposits.

---

Why Your Glasses Have a White Film

If your glasses consistently come out with a cloudy white film, this is almost always one of two things:

Limescale: Hard water deposits on glass surfaces during the drying cycle. Solution: use rinse aid consistently (it reduces water spotting), run a descaler cycle, and ensure you're using the correct amount of detergent for your water hardness. Most dishwasher detergent packaging has a guide for adjusting dosage based on water hardness.

Etching: Permanent microscopic surface damage to the glass from the dishwasher's heat and alkaline detergent over many cycles. This produces a permanent cloudy appearance that cannot be removed — it's damage, not residue. Etching is more common with delicate glassware, crystal, and glasses washed at high temperatures repeatedly. Solution: handwash delicate glasses, or run them on a shorter, cooler cycle.

The test: rub your finger on the cloudy area. If the cloudiness wipes off even partially, it's limescale. If it doesn't move at all, it's etching.

---

Preventing Dishwasher Problems: Ongoing Habits

Scrape but don't pre-rinse. Modern dishwashers are designed to handle food residue — scrape large pieces off plates but don't fully rinse them. Sending dishes into the dishwasher too clean can actually affect the detergent's effectiveness (some detergents need food particles to work against). However, large food chunks should always be scraped off to prevent filter clogging.

Use rinse aid consistently. Rinse aid is not optional in Adelaide's hard water environment. It significantly reduces spotting and helps dishes dry more effectively.

Leave the door open after a cycle. Leaving the door slightly ajar after the cycle finishes allows moisture to escape and reduces the conditions that cause mould growth in the seal. Even opening it for 30 minutes makes a difference.

Clean the filter monthly. Set a reminder. It takes 3 minutes and is the most impactful maintenance habit for dishwasher performance.

Use the hottest cycle for your regular loads. Higher temperatures are more effective at dissolving grease and killing bacteria. Eco cycles save energy but leave more residue in the machine over time.

---

A clean dishwasher runs more efficiently, cleans more effectively and lasts longer. The maintenance routine above takes about 20 minutes once a month and prevents the kind of gradual deterioration that leads to expensive repairs or early replacement.

If you'd like a professional kitchen deep clean that includes your dishwasher, oven and all appliances as part of a full service, book a professional kitchen deep clean in Adelaide.

---

If your oven needs the same treatment, see our step-by-step guide on how to clean oven racks.

---

Written by Victor Jacon — Master Cleaner & Home Detailing Specialist, Founder of PF Cleaning Adelaide.