DIY GUIDE · HOME REPAIRS & HANDYMAN · CHECKED OCTOBER 2026
How to fix a dishwasher that will not clean or drain yourself
An hour. £4–£45 in salt, cleaner or a spray arm, if anything.
Filter, spray arms, sink connection, salt and rinse aid — the owner's checks for poor cleaning and standing water, and where to stop.
- Every step, start to finish
- Checked October 2026 — sources at the end
- Honest about when to call a pro
FIRST, THE HONEST ANSWER
Do it yourself, or get a repairer?
Do it yourself if…
- Water stands in the base at the end of a programme
- Plates come out gritty, glasses come out cloudy or spotted
- The machine smells when you open it
- A spray arm is cracked, will not spin or has blocked holes
Get a pro if…
- The circuit trips when the dishwasher starts, or the plug or cable shows any scorching
- It will not heat at all — cold plates at the end of a hot programme point at the heater or its control
- Water leaks from under the machine with the door seal and the hoses dry
- It hums but the pump will not run with the filter and sump clear
Safety first
- Unplug the dishwasher, or switch off its spur, before any check. The display going off does not mean the pump and heater are dead.
- Never remove the panels under the door or at the sides. Behind them are the pump, the heater, the wiring and the control board.
- Wear gloves in the base; the sump collects broken glass and knife tips.
- Built-in machines are heavy and screwed to the worktop. Do not pull one out on your own or with the hoses connected.
- Any scorching or burning smell at the plug, spur or cable means stop, and do not run the machine again.
Stop here: Under the tub: the pump, the heater and anything wired
The danger is mains electricity close to water. The drain pump, circulation motor, heater and control board sit under the tub behind panels, and a part refitted wrongly can leave the case or the door live. The makers limit owner work to the filter, spray arms, salt, rinse aid, door seal and hoses; past that, book an engineer, and if the machine is under a guarantee, use the maker's own service before anyone takes a panel off. How to hire a dishwasher engineer →
| MATERIAL | COVERAGE | FOR THIS JOB |
|---|---|---|
| Dishwasher salt | Fills the salt reservoir in hard-water areas | One bag; top up when the indicator shows |
| Rinse aid | Fills the dispenser in the door | One bottle lasts months |
| Dishwasher cleaner | One dose per empty hot wash | One dose after cleaning the filter and arms |
| Spray arm, by model number | Genuine part for your model | Only if one is cracked or will not turn |
How often to clean the filter
Count the washes a week and divide by the weekly figure your manual gives. A household running the machine once a day does seven washes a week; on a once-a-week cleaning schedule, that is a filter clean every seven loads. Running it twice a day halves that to every three or four loads.
If you rinse plates before loading, the filter lasts longer; if you scrape straight in, clean it more often.
Food left on, in a pattern, points at the spray arms or the loading. Grit and a film on everything points at the filter. White chalk on glasses points at salt, the hardness setting or rinse aid. Standing water points at the drain path: filter, sump, drain hose and the sink connection. Let the plates tell you which part of the machine to open first.
It sits in the base under the bottom basket, usually a coarse cup that twists into a fine mesh plate. One maker asks owners to clean it once a week, and most machines that drain badly or clean badly have never had it out. It takes five minutes and needs nothing but a tap and a soft brush.
The arms throw water up and down through small holes, and a single pip or a flake of scale in a hole kills its jet. Most arms unclip or unscrew by hand. A clear arm that spins freely is fine; a cracked one is a cheap part bought by model number, and it clips back in the same way it came out.
Salt is not a cleaner: it regenerates the water softener inside the machine, so it only matters in hard-water areas and only if the machine has a salt reservoir. Rinse aid lets the water sheet off glasses instead of drying in drops. If glasses go chalky, top up the salt and check the hardness setting in the manual matches your water supplier's figure.
Run the hottest programme with the machine empty and a dishwasher cleaner, after the filter and arms are clean, not before. One maker suggests an empty intensive or machine-care programme for a deep clean. Cleaning the drum with the filter still full only moves the debris around.
THE PART THAT DECIDES THE FINISH
Before you start — the machine and the space
Find the case that matches what the dishwasher is doing. Every one begins with the machine switched off and the plug out, or its switched spur off.
Standing water in the base
The programme ends with a pool under the bottom basket.
- Switch off and unplug, or turn off the switched spur in the cupboard beside it
- Lay towels on the floor in front of the open door
- Take out the bottom basket so you can reach the filter
- Bale the water out with a cup and mop the rest with a sponge before you twist the filter
Gritty plates and cloudy film
The machine runs and drains, but nothing comes out clean.
- Take out both baskets and look at the spray arms for blocked holes
- Lift out the filter and look for a layer of grease and food
- Check you are using the right amount of detergent, and that it is in date
- Check the arms spin freely by flicking them with a finger
Chalky white marks on glasses
A dry white bloom that wipes off, or will not.
- Find the salt reservoir cap in the base, if there is one, and check its level
- Check the rinse aid dispenser in the door
- Find your water hardness on your water company's website and the setting in the manual
- Try wiping a marked glass with vinegar: if the bloom comes off, it is scale; if not, the glass is etched
Water on the floor
A puddle in front of, or under, the machine.
- Dry the floor and the door seal completely
- Look along the door seal for food stuck in it or a tear
- Check you are not using washing-up liquid; it froths out of the door
- Pull the plinth off and look at the hoses with a torch while a short programme runs
Smells when you open the door
Stale water and old food.
- Clean the filter first, then the sump below it
- Wipe the door seal and the bottom edge of the door where food collects
- Check the drain hose at the sink trap; a backed-up trap feeds the smell into the machine
- Plan an empty hot wash with cleaner to finish
Nothing happens at all
No lights, no fill.
- Check the door is fully latched and the child lock and delay timer are off
- Check the plug or switched spur, and test the socket with a lamp you know works
- Look at the plug and cable for heat damage
- Check the supply tap under the sink is open
THE JOB
How to fix a dishwasher, in order
Isolate the machine and clear the decks
10 minSwitch the dishwasher off, then unplug it or turn off its switched spur. Empty both baskets and the cutlery basket, slide the bottom basket out and put it in the sink. Put towels down in front of the door. Read the case above that matches your fault so you know what you are checking. If there is water standing in the base, bale it out with a cup and soak up the last of it with a sponge before you touch the filter, so the debris does not wash down into the sump.
- Wear rubber gloves; there is often broken glass in the base
- Keep a bowl beside you for what you find, so you can tell what caused it
- Leave the door fully open and the upper basket pushed back out of your way
Mistake to avoid: Lifting the filter out of a pool of water. The food on it drops into the sump and blocks the pump inlet you are trying to clear.
Take out and clean the filter
15 minTwist the coarse filter cup anti-clockwise and lift it out; the flat fine mesh comes with it or lifts out under it. Separate the parts, rinse them under a warm tap and brush the mesh from the clean side outwards with a soft brush. Do not scour it: the mesh is fine and tears. Wipe the filter seat in the base, then look into the sump below it with a torch and fish out anything solid — glass, a bone, a cherry stone, a label. Refit the mesh flat, drop the cup in and twist it clockwise until it clicks.
- A greasy mesh clears with warm water and a drop of washing-up liquid, rinsed well
- If the filter does not click home, the mesh is not seated flat; take it out and start again
- Look under the filter cup at the small grille over the pump; that is where glass ends up
Mistake to avoid: Running the dishwasher without the filter in place, to test it. Debris goes straight to the pump and the repair stops being yours.
Clear and check the spray arms
15 minRemove the lower arm by lifting it straight up or unclipping its centre, and the upper arm from under the top basket, following your manual. Hold each arm up to the light and look through the holes. Clear each blocked hole with a plastic cocktail stick and rinse the arm under the tap, shaking it to get the debris out of the inside. Check each arm for cracks along the seams. Refit, then flick each one with a finger: it should spin several turns freely.
- Rinse from the centre outwards so debris flushes out of the tips, not further in
- A hole you cannot clear means scale inside; soak the arm in warm water and vinegar for an hour
- Check nothing in the baskets hangs down far enough to stop an arm turning
Mistake to avoid: Clearing the holes with a knife tip or a skewer. It widens or scores the jet, and the arm then sprays unevenly for the rest of its life.
Check the drain hose at the sink
20 minUnder the sink, follow the grey drain hose from the back of the cupboard to the sink trap or waste spigot. Look for a kink where the hose is crushed by bottles or the bin. Put a bucket under the connection, undo the clip and pull the hose off the spigot. Look into the spigot: on a newly fitted trap, a sealed blanking disc may never have been cut out; on an old one, sink grease often blocks it. Clear it, flush the trap with a kettle of hot water, refit the hose and tighten the clip.
- The hose should rise in a loop above the trap before it drops into it, so sink water cannot run back
- If the sink itself drains slowly, clear the sink trap first; the dishwasher drains into it
- A new trap with an appliance spigot often comes sealed; cut the disc out cleanly with a knife
Mistake to avoid: Leaving the drain hose low, below the sink trap. Dirty sink water then runs back into the machine and sits in the base.
Salt, rinse aid and the hardness setting
15 minUnscrew the salt cap in the base and top it up with dishwasher salt through a funnel until it is full. The first fill after a long empty spell needs a jug of water as well, as the manual will say. Screw the cap down firmly and wipe up any spilled salt, which corrodes the tub if left. Fill the rinse aid dispenser in the door to its line. Then look up your water hardness and check the setting in the manual matches; a machine set for soft water in a hard-water area leaves chalk on everything.
- Spilled salt in the base: run a rinse programme straight away to wash it out
- In a soft-water area your machine may have no salt reservoir at all, and does not need one
- Turn the rinse aid dose down a step if glasses come out streaky, up a step if they come out spotty
Mistake to avoid: Putting table salt or detergent in the salt reservoir. Detergent there ruins the softener, and that is a part under the tub.
Check the door seal and the bottom edge
10 minRun a damp cloth round the door seal on the tub and look for food stuck in it, flattening, or a split. Wipe the lower edge of the door, which sits outside the tub and collects food and grease that the wash never reaches. Look at the hinges and the springs if the door drops open on its own or will not stay shut; a broken hinge spring is a part you can often order, but fitting it means taking off the side panels, which is engineer territory on built-in machines.
- A seal that is torn lets water out at the bottom corner of the door; it is a part by model number
- Check the door latches with a firm click; a door not fully shut stops the programme starting
- A drop of washing-up liquid on a cloth lifts grease from the door edge
Mistake to avoid: Using washing-up liquid in the dispenser. It foams out round the seal and floods the floor, and looks exactly like a leak.
Look at the hoses and the supply
15 minWith the machine still off, check the supply valve under the sink is fully open. If the machine fills slowly or not at all, turn the valve off, undo the inlet hose at the valve into a cup and look for a mesh filter in the hose end, which clogs with grit. One maker puts the working water pressure for its dishwashers at 1–10 bar. Refit hand-tight plus a quarter turn and check for drips. Pull off the kick plinth and shine a torch under the machine during a short programme, looking for drips from the hose joints.
- Some machines have an anti-flood base that shows a fault code if it finds water; mop it out and find the drip first
- An integrated machine is held to the worktop by two screws at the top; leave them in while you look under it
- If the hose is cracked at the nut, buy a new hose, not tape
Mistake to avoid: Sliding a built-in dishwasher out of its housing with the hoses and cable still connected. It stretches them, and a split hose floods the kitchen.
Run an empty maintenance wash
90 minWith the filter, arms and drain connection clear, put the baskets back, add a dishwasher cleaner as its pack says, and run the hottest programme with nothing else in the machine. Leave the door ajar afterwards to let the tub dry. Then run a normal load and look at the results the way you did at the start: grit, film, chalk, food in a pattern. If it is clean and drains dry, you are done.
- Do this monthly if you mostly use eco or quick programmes
- Wipe the filter seat once more after the cleaning wash; it drops what it lifted
- A cleaning wash on a dirty filter just recirculates the dirt
Mistake to avoid: Skipping the cleaning wash because the machine now drains. The grease left in the sump is what brings the smell back within a week.
Test, and know when to stop
10 minPlug in, switch on and run a short programme while you watch. Listen for the fill, the wash, and the drain. If water still stands with the filter and sump clear and the hose free, or the machine hums without draining, the pump is the next suspect, and it sits under the tub. If the plates stay cold on a hot programme, the heater or its sensor is at fault. Both are behind panels, next to mains wiring, and that is where this guide stops.
- Write down any fault code the display shows; the engineer will want it
- Keep the towels down for the first two or three loads
- Write the date on the inside of the door when you clean the filter, so you know when it is due
Mistake to avoid: Reaching into the sump to turn the pump impeller with the machine plugged in. The pump can start without warning when the programme resumes.
The mistakes that make it worse
- Running the machine with the filter out to see if that fixes the drain
- Clearing spray-arm holes with a metal skewer or knife
- Leaving the drain hose without its loop above the trap
- Putting the wrong thing in the salt reservoir
Stop here and get a dishwasher repair engineer
- Water still stands with the filter, sump and drain hose clear, or the pump hums without draining
- The machine will not heat, trips the circuit, or there is any sign of burning
- Water leaks from under the tub with the door seal and hoses dry
- The door hinges or springs need replacing on a built-in machine
| WHAT YOU SEE | WHY, AND THE FIX |
|---|---|
| Dishwasher not draining, water in the bottom | Blocked filter or sump, a kinked drain hose, or a blocked sink spigot. Bale out, clean the filter and sump, then check the hose loop and the spigot under the sink. |
| Gritty film on plates and glasses | Filter full of food and grease. Take it out, rinse it from the clean side, and clean it weekly from now on. |
| Food left on the top rack only | The upper spray arm is blocked or obstructed. Remove it, clear the holes with a plastic pick, and check nothing in the basket stops it turning. |
| Cloudy or chalky white glasses | Low salt, the wrong hardness setting, or no rinse aid. If vinegar does not shift the bloom, the glass is etched and the damage is permanent. |
| Dishwasher smells bad | Old food in the filter and sump, grease on the door edge, or sink water backing up the drain hose. Clean all three and run an empty hot wash with cleaner. |
| Puddle on the floor in front | Washing-up liquid in the dispenser, food on the door seal, or a torn seal. A puddle with the seal sound and dry points to a hose joint under the machine. |
| Dishwasher does not finish, beeps and stops | Usually a drain or fill fault code. Check the filter, the drain hose and the supply valve, and look up the code in the manual before you call anyone. |
| Plates come out cold and wet on a hot programme | A heating fault. Check the rinse aid first, then stop: the heater and its control sit under the tub. |
WHAT YOU SAVE
What it costs to do it yourself
| Dishwasher salt, 1 kg | £4–£5 |
|---|---|
| Appliance trap adaptor, if the spigot is broken | £6–£7 |
| Drain hose, by model | £10–£12 |
| Spray arm, by model | £12–£32 |
| Total, a typical cleaning or drain fault | £4–£45 |
| DIY total | £4–£45 |
Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.
Most dishwasher faults are fixed with a tap, a brush and an hour. A part bought by model number is still well below an engineer's call-out; the pump, heater or board is what the price guide band covers.
RATHER NOT?
Dishwasher engineers near you, with prices shown
The ones who cover your area, nearest first, with one score from every review. No account needed to look.
Or post the job free and let them come to you.
Rinse the filter once a week, look at the arms once a month and run an empty hot wash with cleaner if you mostly use short programmes.
Leave the door ajar for an hour after the last wash of the day. A closed warm tub grows the smell back.
A broken spray arm or hose goes in general waste. A whole dishwasher is electrical waste: the retailer selling you a like-for-like one must take the old one back free, and your council takes it as a bulky collection or at the household waste recycling centre.
Register the dishwasher with the maker so recall notices reach you, and keep the model number with the manual.
Fixing a dishwasher that will not clean or drain: questions people ask
A blocked filter or sump, a kinked drain hose, or a blocked spigot on the sink trap. Unplug it, bale out, clean the filter and sump, then check the hose and the spigot.
One maker asks for once a week, or whenever it is clogged. If you scrape plates straight into the machine without rinsing, clean it more often.
A film that comes off with vinegar is scale: top up the salt, check the hardness setting and fill the rinse aid. A cloud that will not come off is etching, which is permanent; use a gentler programme and less detergent for glasses.
One maker gives 1–10 bar for its machines. A slow fill is more often a part-closed valve or a clogged mesh in the hose end than low mains pressure.
Not as a home job. It means tipping the machine, removing the base panels and working beside the wiring and heater. The owner's work stops at the filter, sump, arms, seal, salt and hoses.
On the Locufy UK price guide a repair costs £60–£250 per repair, typically £150. A pump or heater sits at the upper end; a call-out that finds a blocked filter is money you can save.
MORE GUIDES
More DIY guides
Sources — checked October 2026
- Beko — how to clean a dishwasher: filter once a week, spray arms, no sharp objects
- Beko — how to install and connect a dishwasher: 1–10 bar, 13 A RCD-protected socket, drain hose bung
- HSE — portable appliance testing FAQs: the user's visual check
- GOV.UK — WEEE regulations: free like-for-like take-back by retailers
- GOV.UK — dispose of household waste: electricals, the council and the recycling centre
- Beko spare parts shop — dishwasher parts, price check October 2026
- Beko accessories shop — dishwasher salt, price check October 2026
- Wickes — appliance trap adaptors, price check October 2026