Dishwasher deep cleaning

What does a dishwasher deep clean include?

Everything below the bottom rack, and most of what’s above it. The racks come out first. Then the filter assembly, which on most machines is a coarse basket over a fine mesh screen, unscrews from the floor of the tub, and under it is the sump: a shallow well where the wash water collects, and where the grease and the bits of food that got past the filter have been sitting in warm water since the machine was new. We clear it by hand. The spray arms come off next, because the jets clog with seeds, glass chips and scale, and a spray arm with three blocked jets is why the top rack comes out dirty.

The door gasket, the door edge and the hinge channel get degreased. The tub gets descaled where there’s scale. Then it all goes back, we run an empty cycle on the hottest setting, and we check that the machine drains fully and that the door seals along its whole edge before we call it done.

Why does my dishwasher smell?

Grease in the sump, nearly every time. A dishwasher’s job is to wash grease off plates, and that grease has to go somewhere. Some of it drains. The rest cools, settles in the sump and the filter, and coats the underside of the tub floor where no cycle touches it. Warm, wet and dark is all it needs. The second place is the door gasket, especially the bottom edge and the corners, where rinse water pools and dries and pools again. The third is a drain hose that sags and holds water.

Rinse aid, tablets and the “dishwasher cleaner” products do help with scale. They don’t do much for a layer of grease that’s been building for years, because they’re designed to run through the machine, not to sit on a surface and lift it. The fix is mechanical: take the parts out and clean them. It’s the least glamorous thing we do and the one people thank us for most, because the smell that met them every time the door opened is gone that afternoon.

Miele, Bosch, Cove and Fisher & Paykel: what’s different

Not much in principle, a lot in the parts. Miele and Bosch use a multi-piece filter that unscrews from the tub floor and a sump you can reach by hand; Miele’s stainless interior shows scale early and polishes back well. Cove, the dishwasher from the Sub-Zero and Wolf family, has a removable filter and spray arms that pop off, with interior lighting that makes a dirty tub very obvious. Fisher & Paykel DishDrawers are the odd one: two independent drawers, each with its own small filter and rotor, and the drawer rails and lid seals collect what a full-size tub’s gasket would. We clean both drawers as separate machines, because that’s what they are.

How a dishwasher tells you it’s due

The signs are easy to read once you know them: a smell when the door opens, cloudy glasses, grit on the top rack, water standing in the bottom after a cycle, or dishes coming out wet when they used to come out dry. Any one of those is enough. Two of them together and the sump is almost certainly the reason.

The filter is the homeowner’s part, and rinsing it under the tap whenever it looks loaded is a thirty-second job worth doing. The full teardown, sump and arms and gasket, is the part almost nobody does in between, and it’s the part that matters. What that machine needs, and when, is something we work out with you once the filter is out and you can see the sump for yourself.

Booking it with the kitchen visit

A dishwasher on its own is a small job, and we’d rather do it while we’re already there with the floor covered and the tools out. Most of our dishwasher work happens alongside steam-cleaning the oven the same day or the range hood, and the fridge usually joins the list, since condenser coils and ice makers share the visit without adding much time.

Tell us the brand and whether it’s a full-size tub or drawers when you book it with your kitchen visit.