Dishwashers are not silent appliances and a lot of what people report as a fault is normal: the drone of the wash pump, the hiss of a fill, the click of the detergent door, a short buzz as the drain pump runs. What is not normal is a hard grinding, a rhythmic knock, a rattle that changes when you move the racks, or a rising whine that was not there last month. Each of those has a distinct source, and one of them costs nothing to fix, which is why it goes first.
Read this first
- Switch off the breaker before removing the sump cover or reaching into the pump area.
- Broken glass is the most common thing found in a noisy sump. Look with a flashlight before you put a hand in, and use pliers rather than fingers.
- Let the machine cool before reaching inside after a heated cycle — the element and the water are both hot enough to burn.
- A machine that has worked loose from the countertop can tip forward when the loaded door is opened. Refit the mounting brackets before using it.
Step by step
Note when in the cycle the noise happens
This narrows it faster than any physical inspection. Noise during fill points at the inlet valve or the household plumbing. Noise during the wash phase points at the circulation pump, the spray arms, or something loose in the tub. Noise only at the start and the end, lasting under a minute, is the drain pump. Run a cycle with the kitchen quiet and write down the timing. A sound that happens at every phase equally is usually the cabinet or the mounting rather than a component.
Check the sump for something hard
A hard grinding or clattering during wash is very often a foreign object being thrown around by the pump — a chip of glass, a fruit stone, a small bone, a bottle cap, a piece of a broken tine cap. Switch the breaker off, pull the filter, and look into the sump with a flashlight. Remove anything you find with long-nose pliers, not fingers. A noise that appeared suddenly rather than growing over months fits this cause closely, and clearing it is free, so do it before anything else.
Spin the spray arms by hand
Turn each arm through a full rotation and watch it. It should spin freely without touching anything. A tall item in the lower rack, a pan handle poking through, a rack loaded past its capacity, or a sagging upper rack will all let an arm strike on every pass, which reads as a rhythmic knock or scrape. Check the arm itself for a cracked hub or a split seam, and check the retaining nut is snug — a loose arm wobbles and clatters against the rack above it.
Check the racks and their rollers
Pull each rack fully out and look at the rollers and the adjuster mechanism on the upper rack. Missing or split rollers let a loaded rack sit crooked, which drops it into the spray arm's path, and a rack that is not seated rattles against the tub through the whole cycle. Check the tine caps too — a missing cap leaves bare wire that lets items shift and clink. All of this is inexpensive, and rack parts are among the first things discontinued on an older machine, so check availability early.
Tell the drain pump from the circulation pump
These sound different and run at different times. The drain pump is a high-pitched whir or buzz that runs for well under a minute at the start of the cycle and again at the end. The circulation pump is a steady drone that runs through the whole wash. A drain pump that has become loud or rattly usually has debris against the impeller — the same inspection as the sump. A drain pump that buzzes without moving water is jammed, and that is a different fault.
Listen for a rising whine from the circulation pump
A wash drone that has gradually become a whine, a howl, or a metallic scrape over months is a bearing in the circulation pump wearing out. This is the one genuinely expensive noise on a dishwasher. Confirm the arms are clear and the sump is clean first, because a starved pump gets loud for reasons that cost nothing to fix. If it really is the pump, price the repair against a new machine before committing — on a mid-market dishwasher this repair crosses a lot of the replacement cost.
Check the machine is secured and level
A built-in dishwasher is fixed to the underside of the countertop or the adjacent cabinets by two brackets, and those screws work loose. An unsecured machine walks and drums against the cabinetry through the wash, which sounds far worse than it is. Check the brackets, check the machine is level side to side using the adjustable feet, and check the toe kick panel is properly fitted — a loose kick plate buzzes convincingly enough that people replace pumps over it.
Rule out the plumbing before blaming the appliance
A hard bang or knock at the exact moment the machine stops filling is water hammer in the household pipes, not a dishwasher fault. It happens because the inlet valve closes fast and the moving column of water has nowhere to go. A gurgle from the sink while the machine drains points at the waste line or the venting. Neither is fixed by anything inside the appliance, and recognising them saves a wasted service call.
What this repair costs
Doing it yourself
$0–$130
Hiring a technician
$150–$450
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
Call a technician when the noise is a whine or scrape from the circulation pump with the arms and sump confirmed clear, since that is a pump and motor replacement and on many machines it approaches the cost of a new one — get the quote and the age of the machine on the table together. Call a plumber for water hammer, gurgling drains and anything that happens in the pipes rather than the appliance. And take any machine out of service that has ground up glass and now leaks, because glass through a pump seal is what turns a noise into a leak.
More dishwasher guides
- Dishwasher Not Cleaning — Find Out What It Is Short Of30–60 minutes
- Dishwasher Not Draining — Clear the Standing Water20–60 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