Kitchen appliances
Five dishwasher faults that are almost always the filter
When a dishwasher stops doing its job, the dishwasher filter is the first place to look. It sits in the floor of the machine and catches everything that washes off your plates, quietly, until it fills up. Once it is full, the symptoms can look like serious dishwasher faults. In most cases they are not.
In short: dirty dishes, standing water, smells, a grubby top basket and odd noises nearly always trace back to a blocked dishwasher filter. Cleaning it takes a few minutes and fixes most of them. If it does not, the fault is usually a pump, a hose or an arm, and all three are repairable.
Before you start: switch the dishwasher off at the socket or fused spur before putting a hand in the base. Wear gloves if there is any chance of broken glass.
Grit, food bits or a greasy film on clean dishes
Glasses feel sandy, plates have specks on them and cutlery comes out with a greasy film.
Your dishwasher does not use fresh water for the whole cycle. It pumps the same water round through the filter and back out of the spray arms. When the filter is full, food and grease pass straight back over the dishes you are trying to clean.
Quick check: look at the base of upturned cups and glasses. Grit collects there first.
Water sitting in the bottom after the cycle
Water across the floor of the machine, or lapping around the bottom of the lower basket, once the cycle has finished. Some machines add a drainage error code, or refuse to start the next wash until the water has gone.
The drain pump pulls water out through the filter. A clogged mesh slows it to a trickle and the cycle ends before the water has cleared.
Quick check: a little water in the filter well is normal and keeps the seals from drying out. Water above the filter is not.
A bad smell when you open the door
A sour, stale smell every time the door opens, even after a wash. Rinse aid and dishwasher cleaner mask it for a cycle or two and then it is back.
Food trapped in the filter is warm and wet for hours at a time. Left for a few weeks it starts to break down, and the smell finds its way into the kitchen every time the door is opened. Only a clean filter fixes it.
Quick check: while the filter is out, wipe the rubber door seal and the bottom edge of the door. Both trap the same residue.
The top basket comes out dirtier than the bottom
Cups and glasses up top come out cloudy or spotted while the plates below look fine.
Water reaches the upper spray arm under pressure from the circulation pump. A blocked filter starves the pump, pressure drops and the top arm is the first to lose out. If the filter has been left unlocked or the mesh is split, small debris also gets through and blocks the jets in the arm itself. If every glass is cloudy but nothing feels gritty, top up the salt and rinse aid first. That haze is limescale, not food, and no amount of filter cleaning shifts it.
Quick check: lift the upper arm out, hold it up to the light and clear any blocked jets with a cocktail stick.
A humming, grinding or gurgling noise
A hum with no sound of water moving, a sharp grinding or rattling during the wash, or gurgling as the machine drains.
A hum is often the pump straining against a blocked filter. Grinding is more likely something solid, such as a fragment of glass, a fruit stone, a piece of bone or a label from a jar, sitting in the filter housing where the water enters the pump. Gurgling means the drain is struggling, for the same reason as fault two.
Quick check: switch off at the socket, lift the filter out and check the well underneath. Anything hard should come out with it.
Found yours? The fix is below. Rather not put your hand in the base? Book a repair and we will do it.
How to clean a dishwasher filter
Most dishwasher filters come out without tools and go back in the same way. The whole job takes a few minutes.
- Switch offTurn the machine off at the socket or fused spur and pull out the lower basket.
- Find the filterOn most machines it is a round cylinder in the floor of the tub, next to or beneath the lower spray arm. Twist it anticlockwise and lift it out. The flat mesh plate underneath usually lifts out too. A few machines have a self cleaning filter under a fixed grille instead, so if there is nothing to twist, check the manual before pulling at anything.
- Rinse both partsHold them under a warm tap. Use washing up liquid and a soft brush on grease. Avoid anything stiff enough to tear the mesh.
- Check the wellWipe out the space the filter sat in and remove anything solid. If your manual shows how to open the drain pump cover, check in there as well.
- Refit and lockTurn the filter until it locks. A filter that is not locked lets debris straight through to the pump.
- Run a hot washRun a hot wash on an empty machine to flush out anything loosened.
How often should you clean the dishwasher filter
Scrape, do not rinse. Rinsing wastes water and modern detergents are made to work on food that is still there, which is why Waterwise gives the same advice. Just keep the big pieces, bones and labels out.
Dishwasher faults that are not the filter
If the filter is clean, seated and locked and the fault is still there, the cause is usually one of these. All of them are repairable, and Recycle Your Electricals suggests getting a repair quote before you write any appliance off.
- Drain hoseKinked, crushed or blocked, often where it joins the sink waste
- Drain pumpWorn, or jammed by something that got past the filter
- Spray armCracked, blocked or not clipped on properly
- Heater or circulation pumpShows up as cold water and dishes that never dry
- Door seal or float switchLeaks, or a machine that will not fill
Worth repairing
A dishwasher with a worn pump or a damaged hose is still a good dishwasher, and putting it right costs a fraction of replacing it. Since 2021, manufacturers have had to keep dishwasher spares available for years after a model is discontinued, so parts are usually easy to get. Nothing goes ahead without your say so: you approve any parts before we fit them.
Dishwasher filter questions
What are the most common dishwasher faults?
Not draining, not cleaning properly and leaks are the three dishwasher faults reported most often, followed by smells, noise and error codes. The first two, and most of the smells and noises, come back to the filter more often than any other single part. Leaks are a different job and usually need an engineer.
Is water in the bottom of a dishwasher normal?
A small amount in the filter well is normal and keeps the seals from drying out. Water across the floor of the tub after a cycle is not, and usually points to the filter or the drain.
How often should a dishwasher filter be cleaned?
Monthly for most homes. Every couple of weeks if the machine runs every day or plates go in without a scrape first.
Can a blocked dishwasher filter damage the machine?
Over time, yes. Debris that gets past a full or unlocked filter ends up in the drain pump, and a pump working against a blockage every cycle wears sooner than it should.
I have cleaned the filter and it is still not cleaning properly. What next?
Check the spray arm jets and the drain hose, then book a repair. It is usually a pump or an arm, and both are worth fixing.