What it usually means, the likely causes in order, what to safely try first, what a pro charges in Canada, and when to stop and call one.
This guide covers the common cases. Describe your exact problem and get a personalized diagnosis — free to start, with a DIY vs. call-a-pro verdict and a real cost estimate.
A dishwasher that runs a complete, normal-sounding cycle and still leaves grit, film, or food on the dishes is failing at one of three jobs: moving water (spray arms and pump pressure), getting enough water (inlet supply), or keeping the water clean (filters and buildup). The encouraging pattern here is that the top causes are maintenance, not parts: clogged spray-arm jets, a filter mat at the bottom of the tub, and mineral film that an empty cleaner cycle dissolves. Work the maintenance list first — it resolves most 'dirty dishes' complaints without a single tool beyond a toothpick.
Not urgent — no damage is being done, and the dishes can be rewashed by hand in the meantime. It becomes worth booking help if the machine also starts leaving standing water in the tub after a cycle (a drain problem developing) or if cleaning the arms and filter and running a cleaner cycle twice changes nothing, which is when an inlet valve or pump issue becomes the likely story.
The spray arms clean by jets of water, and their small holes clog with mineral scale and food particles, especially the end jets that drive the arm's rotation. A clogged arm both sprays weakly and may stop spinning entirely — dishes on the far side come out untouched.
Most modern dishwashers have a removable filter at the bottom of the tub that traps food soil. Neglected, it mats over until the wash water being recirculated is itself dirty — dishes get 'cleaned' with gritty water no matter how good the detergent is.
Mineral deposits coat the tub, arms, and the dishes themselves, producing the classic cloudy-glass complaint. It builds gradually, so it gets blamed on the machine or the detergent when it's really the water plus time. A cleaner cycle is the test and the treatment.
If the machine under-fills, the pump cavitates and spray pressure drops — cycles sound splashier and less forceful than they used to. An inlet valve screen clogged with sediment from the supply line produces the same symptom.
A tall pan or tray can block an arm's rotation or shield everything behind it, and detergent pods dropped in the bottom (instead of the dispenser) dissolve during the pre-rinse and leave the main wash soap-less. Boring, common, and free to fix.
| Job size | Typical estimate (CAD) |
|---|---|
| Simple fix — the straightforward version of this repair | $110–$250 |
| Major job — complex, hidden, or replacement-level work | $300–$900 |
Estimates only, calibrated to Greater Toronto Area trade rates and adjusted by region on this site — not a quote. Your exact price depends on the cause, parts, and access. A personalized diagnosis narrows this range using your specific symptom.
Arms, filter, cleaner cycles, and loading fixes are exactly what owner manuals describe — do all of them before paying anyone. Call a pro when cleaning changes nothing (inlet valve or wash pump territory), when the tub isn't draining fully, or when error codes appear; bring the model number and describe which racks come out dirty, since top-rack-only versus everything is a real diagnostic clue about which arm or level is failing.
The top rack is served by its own spray arm and feed tube. If the bottom comes out clean and the top doesn't, check that the upper arm spins freely, that its jets are clear, and that the feed tube at the back of the tub seats properly when the rack slides in — a mis-seated connection starves the upper arm of pressure even when everything else works.
Usually it's mineral film, not damage: hard-water deposits that a cleaner cycle and rinse aid largely reverse. True etching — permanent cloudiness from soft water plus strong detergent over time — doesn't polish off. A vinegar rinse on one glass is a quick test: if the cloudiness wipes away with vinegar, it's film; if it doesn't, it's etching.
Scrape, don't rinse. Modern detergents and soil sensors are designed for food residue on the dishes — fully rinsed dishes can actually cause the machine to run a gentler cycle and the detergent to work less effectively. Removing bones and large scraps is plenty, and it protects the filter from clogging as fast.
Often enough that it never mats — for most households, a quick rinse every month or so keeps wash quality from sliding, and more often if you load heavily soiled dishes without scraping. It takes two minutes once you know where it is, and it's the maintenance item most owners have never been told exists.
Describe what's actually happening and get a personalized diagnosis — DIY vs. call-a-pro verdict, real cost estimate, and top-rated local pros.