The Filter in the Floor of the Tub: Two Minutes, No Tools

The single best two minutes anybody spends on this appliance

There is nothing else on this site with the same ratio of effort to benefit. It takes two minutes, it needs no tools, and it prevents a good proportion of both the complaints people call us about on a dishwasher: water that will not drain, and dishes that come out gritty.

And most of these filters have never been out. Not neglected exactly — simply unknown. The machine is silent, integrated, panel-ready, and behaves like a cabinet door, and nothing about it suggests there is a serviceable part in the floor of it.

What it is doing down there

The filter catches food that comes off the load so it is not pumped back over the dishes. That is the whole job, and it works well, which is the problem: everything it catches stays there.

Over a year the mesh takes on a film of grease and starch that water no longer passes through freely. The machine keeps trying, the pump keeps pulling, and two things happen. Drainage takes longer than the control expects, which is exactly what a C1 or C2 message reports. And the wash water carries what the filter can no longer hold, which comes back onto the load as grit.

So this one part sits behind two entirely different complaints, and neither of them looks like a filter problem from the outside.

Getting it out

Roll the lower rack out. Look at the floor of the tub, under where the lower spray arm sits. There is a cylinder standing there in a flat mesh screen.

The cylinder turns about a quarter turn counter-clockwise and lifts straight out. Hand pressure. If it will not move, check you are not turning the spray arm above it, and if it is genuinely stuck pour warm water over it and wait a minute — hardened grease is the usual reason, and force is how the tabs break.

The flat screen underneath comes out too, either with the cylinder or after it.

Cleaning them properly

Warm tap, soft brush on the mesh. What you are removing is a film rather than debris, and water alone runs straight over it.

Running the parts through a dishwasher cycle sounds sensible and does very little, because a wash cycle is what put the film there in the first place.

While they are out, look down

With the filter removed you can see the sump and the pump inlet. This is where things too big for the mesh end up: a shard from a broken tumbler, the paper label off a jar, a fruit sticker, a small bone. Any one of them stops a pump dead, and a pump straining against an obstruction sounds exactly like a pump failing — which is how perfectly good pumps get replaced.

Fingers, not tools, and mind the glass.

Seat it properly on the way back

The screen goes back flat, the cylinder drops in, and it turns clockwise until it stops. This bit matters. A filter that is sitting proud lets debris past it straight to the pump, which is worse than a dirty filter that is doing its job.

How often, honestly

Every few months for a household running the machine most days. Twice a year for lighter use. And once now, whatever the answer to that is, because the first one is always the worst one.

If the machine has also been draining slowly, do this before you book anything. It resolves a real share of those calls, and we would rather tell you that than come out and unscrew something you could have unscrewed yourself.

What comes off it tells you something

Look at what is on the mesh before you rinse it away, because it is a fair description of how the machine is being used.

A grey-brown film and very little solid. Normal, and the interval is about right. This is grease and starch out of the wash water, which is exactly what the filter is for.

Visible food. Plates are going in with too much on them. These machines do not need dishes rinsed — modern detergent needs something to work on — but they do need bones, skins, peel and the last inch of a bowl of cereal scraped off. What the filter catches is what the spray arms were pushing around the load.

Grit and sand. Almost always from produce, and in a house with a garden or a beach habit it is worth knowing that a filter fills faster.

A white chalky deposit. Scale, from local water. That is the same deposit forming inside the spray arms and on the heating element, and it is the argument for descaling the machine rather than only cleaning the filter.

Glass. Stop and be careful with your hands, and check the sump properly. A tumbler that broke three months ago leaves fragments that migrate for a long time afterwards.

The two things people do that make it worse

Running the filter through a cycle instead of cleaning it. The film on the mesh was deposited by wash water. More wash water does not remove it. Thirty seconds with a brush does.

Leaving it out. It happens — the filter comes out, gets put on a windowsill, and the machine runs without it for a week because nothing complains. What is happening in that week is that everything the filter would have caught is going straight to the drain pump, and the pump is the expensive component in this conversation. If the filter is out, the machine does not run.

While the rack is out anyway

Two more minutes buys the rest of the wash performance.

Take the lower spray arm off and hold it to the light. It lifts or unscrews depending on the model. Blocked jets are invisible from above and they change the spray pattern completely — an arm that turns slowly covers half the load.

Look at the door gasket folds. They are warm, damp and shut for most of the day, which is a better environment for mold than anything in the refrigerator. Warm soapy water and a soft brush, folds opened out.

Check the rinse aid. An empty reservoir is the single most common reason glassware suddenly starts spotting, and people almost never look.

None of that is a repair. All of it is what a wash-performance visit begins with, and doing it yourself twice a year means the visit is about something real when it happens.