How often should you clean a dishwasher filter?

Short answer

The filter every month, a full clean every 1 to 3 months. The filter is a round or cylindrical screen in the floor of the dishwasher under the lower spray arm, and it catches everything that comes off the dishes. Rinsing it takes a few minutes. The full clean adds a vinegar cycle and a wipe of the door seal and the spray arms. Together they take 15 to 20 minutes and cost $0 to $5.

Why it matters

A dishwasher doesn't send food down the drain on its own. The filter traps it, so the pump can recirculate clean water over the dishes through the whole cycle. When the filter is full, the water it recirculates carries bits of the last meal, and those bits end up stuck to the glasses on the top rack. That's where gritty dishes come from, and it's why a dishwasher that cleaned well for years seems to stop working.

A full filter also holds a soggy mat of food that starts to smell within days, and the smell comes out every time the door opens. Grease and soap scum build on the door seal and in the spray arm holes, so the arms spray weakly and the seal grows mildew. The drain pump works against all of it. Monthly attention to the filter keeps the dishwasher cleaning the way it did new, and keeps the kitchen from smelling like the inside of it.

When to do it more often

No modifiers are listed, because the filter is already on a monthly schedule. What moves the full clean to the short end of its range is use: a family dishwasher that runs every day loads its filter faster than one that runs twice a week, and a household that doesn't scrape plates before loading fills it faster still. If you see food in the filter basket after a couple of weeks, check it every couple of weeks.

What you need

A soft brush or an old toothbrush, for the filter screen and the spray arm holes
White vinegar, baking soda, or a dishwasher cleaner tablet

Steps at a glance

Pull out the lower rack and lift out the lower spray arm if it sits over the filter.
Twist the filter counterclockwise and lift it out, along with the flat screen beneath it if there is one.
Rinse both under the tap and scrub the mesh with the brush until it's clear.
Wipe the floor of the dishwasher where the filter sat, then put the filter and arm back.
For the full clean, wipe the rubber door seal and the bottom edge of the door, then clear the spray arm holes with a toothpick.
Set a cup of vinegar upright on the top rack and run a hot cycle with the dishwasher otherwise empty.

You're done when the filter mesh is clear, the seal is clean, and a cycle leaves no smell and no grit.

Signs it's overdue

Bits of food on dishes that come out of the cycle.
A bad smell when the door opens.
Standing water in the bottom after a cycle, because the filter is slowing the drain.
Cloudy glasses, from dirty water recirculating over them.

DIY or pro

This is an easy job that the dishwasher is designed for. The filter twists out by hand on nearly every model made in the last couple of decades, and the manual shows where. Older dishwashers with a self-cleaning grinder have no filter to remove, and for those the vinegar cycle and the seal wipe are the whole job.

Nobody sells dishwasher cleaning as a service. A technician's visit, at the same price as any appliance call, is for a dishwasher that still won't drain or still smells after the filter and the drain hose have been cleared, which points at the pump.

FAQ

Where is the dishwasher filter?

In the floor of the tub, under the lower spray arm. It's usually a round cap you twist to unlock and lift out, with a flat screen beneath it.

Can I run the dishwasher without the filter?

Not for long. Food goes straight to the pump and the drain line, and a jammed pump is an expensive repair.

Why do my dishes come out gritty?

The filter is full, so the water spraying the dishes carries food bits from the last load. Clean the filter and the grit stops.

Is vinegar bad for a dishwasher?

A cup in an otherwise empty cycle every month or so is fine and clears grease and scale. Running it with every load can wear the rubber seals over time.