An inch or two of water left in the bottom of a dishwasher at the end of a cycle almost always means a blockage rather than a dead pump. The drain path runs filter, sump, check valve, drain hose, then either a disposal or an air gap and out — and there are exactly five places it can clog. Work along the path in order and most people find it in the first two.
Read this first
- Switch the dishwasher off at the breaker before reaching into the sump or removing the pump cover.
- Broken glass hides in dishwasher sumps — use a flashlight and gloves rather than bare fingers.
- Bail out the standing water first; tipping or pulling out a full dishwasher dumps several litres on the floor.
Step by step
Bail out the water first
Scoop the standing water into a bucket with a cup, then finish with a turkey baster and towels. You need the tub dry to see what you are doing, and you cannot pull the machine out or open the pump with several litres sitting in it. While you are down there, note whether the water smells stale, which suggests it has been sitting for more than one cycle.
Remove and clean the filter and sump
Modern dishwashers have a cylindrical filter assembly in the tub floor that twists out, often with a flat mesh screen beneath it. Take both out and wash them under hot running water with a brush. Then look into the sump underneath with a flashlight and clear labels, seeds, fruit stickers, bits of glass and bone. A neglected filter is the single most common cause of poor drainage, and manufacturers expect it cleaned monthly.
Check the disposal — including the knockout plug
If the dishwasher drains into a garbage disposal, run the disposal for thirty seconds first; a disposal full of waste blocks the dishwasher's drain outright. Then, if the disposal was replaced recently, check the knockout plug. Every new disposal ships with a solid plug moulded into the dishwasher inlet that must be punched out before connection — leaving it in is one of the most common post-installation failures and gives you a dishwasher that has never drained since the day the disposal went in.
Clear the air gap
If there is a small chrome cylinder on the counter beside the faucet, that is the air gap, required by code in many jurisdictions. Twist off the cap and the cover underneath and look inside — they pack with food debris and starch. Clean it out and flush it. A clogged air gap typically shows itself by spitting water onto the counter during drain as well as leaving water in the tub.
Check the drain hose for kinks and the high loop
Pull the machine out or look under the sink. The drain hose must rise to a high loop under the counter, above the level of the sink drain connection, so dirty sink water cannot siphon back. Check that the hose is not crushed behind the machine, kinked where it exits the cabinet, or crimped under a leveling foot. Disconnect it at the disposal end and blow or flush through it to confirm it is clear.
Inspect the check valve and drain impeller
With the power off at the breaker, remove the sump cover or pump cover inside the tub — usually one or two screws and a retaining clip. Look at the check valve flapper, which should move freely and seal; a flapper stuck open lets water back in, and one stuck closed blocks the drain. Then check the drain impeller for a shard of glass, a fruit pit or a twist tie wrapped around it, which will stall the pump every time.
Run a drain test and listen
Reassemble, restore power, and start a cycle then cancel it — most machines run a two-minute drain when you cancel. Listen at the machine. A steady hum with no water movement means the pump is energised but blocked or the impeller is stripped. Silence means the pump is not being told to run, which points at the control or the wiring. Water draining normally means you found it.
What this repair costs
Doing it yourself
$0–$80
Hiring a technician
$150–$350
Prices are general estimates for typical US jobs, not quotes. What you actually pay depends on your appliance's brand and age, the part required, your region, and each shop's labour rate. The DIY figure assumes you supply the labour and buy the part yourself.
Parts you may end up buying
| Part | Install | Typical price | Typical lifespan |
|---|---|---|---|
| Spray Arm | easy | $15–$40 | 5–8 years |
| Inlet Valve | moderate | $15–$40 | 8–12 years |
| Drain Pump | moderate | $35–$120 | 8–12 years |
| Door Latch and Switch Assembly | easy | $20–$80 | 6–12 years |
| Heating Element | moderate | $25–$85 | 8–14 years |
| Float Switch | easy | $10–$35 | 10+ years |
| Door Gasket | easy | $20–$75 | 6–12 years |
| Rack Roller and Adjuster Kit | easy | $12–$50 | 5–10 years |
| Detergent Dispenser | moderate | $30–$100 | 8–12 years |
| Circulation Pump and Motor | advanced | $90–$330 | 8–14 years |
Still not fixed
When to call a pro
If the drain path is clear end to end and the pump hums without moving water, the drain pump needs replacing — a $60–$150 part that is a moderate DIY job on some models and a machine-out, tip-it-over job on others. If the pump is completely silent during a forced drain and you have confirmed power at the machine, the control board is not commanding it, and that is a diagnosis worth paying for. A drain line that backs up into the sink as well as the dishwasher is a plumbing problem.
More dishwasher guides
- Dishwasher Not Cleaning — Find Out What It Is Short Of30–60 minutes
- Dishwasher Leaking — Find the Source Before It Damages the Floor30–90 minutes
- Dishwasher Not Drying Dishes — Why, and What Actually Helps15–45 minutes
- Dishwasher Soap Dispenser Not Opening — Why the Pod Is Still There20–60 minutes
- Dishwasher Spray Arm Not Spinning — Restore the Wash Action20–45 minutes
- Dishwasher Door Won't Latch or Stay Closed30–90 minutes
- Dishwasher Won't Start — Work Through the Lockouts First30–75 minutes
- Dishwasher Not Filling With Water — Trace the Supply45–90 minutes
- Dishwasher Smells Bad — Clear the Sources in Order45–90 minutes plus a cleaning cycle
- White Film on Dishes — Hard Water Scale or Permanent Etching?30 minutes plus a test cycle
- Dishwasher Making Noise — Match the Sound to the Part30–75 minutes