There's a moment every dishwasher owner knows: you pull out a wine glass, hold it to the window, and it's foggy. Or you run a finger across a plate you thought was clean and feel sand. Neither means the dishwasher is dying. Both mean something in the cleaning process has gone wrong, and there are only a few things it can be.
This guide sorts the causes into the ones you can fix today and the ones that point to a worn part.
Is the fog removable?
Before anything else, find out what the cloudiness is. Soak one of the affected glasses in plain white vinegar for five minutes, then rinse it.
- •The glass comes out clear. The film was mineral deposits left behind by your water. It's removable, and it can be prevented.
- •The glass stays cloudy. That's etching: microscopic damage to the glass surface itself. It can't be undone. It tends to come from very soft water combined with too much detergent, or from very hot washes over a long period. The fix is going forward, not backward: less detergent and gentler cycles for good glassware.
This single test changes every step that follows, so don't skip it.
Mineral film: where it comes from
All tap water carries some dissolved minerals. When a thin layer of water dries on a glass, it leaves them behind. The amount varies by supplier and even by season. In the Pittsburgh area, water comes from several different suppliers depending on where you live, including Pittsburgh Water in much of the city and Pennsylvania American Water, West View Water Authority and others in the suburbs. If you want to know how hard your water is, your supplier publishes that in its annual water quality report.
Whatever your water, the same measures keep film under control.
Rinse aid
Rinse aid lowers the surface tension of the final rinse so water sheets off instead of drying in droplets. It matters more than most people think, and on dishwashers that dry by condensation it's close to essential. Check the dispenser, usually a round cap next to the detergent cup. Many have an indicator that goes clear or dark when empty. If yours has an adjustable dose setting, turning it up a step or two often clears persistent spotting.
Detergent
Use fresh detergent. Powder that has sat in a damp cabinet under the sink clumps and dissolves poorly. Pods and tablets should go into the detergent cup, not loose in the bottom of the tub, unless the manufacturer says otherwise. And more isn't better. Too much detergent in soft water is exactly how etching begins.
Clean the tub
If the inside of the dishwasher is chalky, run an empty cycle with a commercial dishwasher cleaner or a cup of white vinegar standing upright on the top rack. Scale builds up on the heating element and in the spray arms as well as on your dishes.
Grit, sand and bits of food
A gritty film on plates is almost always food that was washed off one dish and redeposited on another. That happens when the dishwasher can't get the dirty water out of circulation.
The filter
Most dishwashers made in the last decade or so have a manual filter: a cylinder and flat screen under the bottom spray arm. Unlike older self-cleaning designs with a grinder, it has to be cleaned by hand. Many owners don't know it's there.
Twist it out (it usually turns a quarter turn counterclockwise), rinse it under hot water, and scrub the mesh gently with a soft brush. Look into the opening below it for broken glass, olive pits or labels. Put it back and lock it fully, because a loose filter lets debris bypass it and reach the pump.
If it hasn't been cleaned in a long time, expect grease and a smell. Once a month is a reasonable habit.
The spray arms
Take the arms off (most pop off or unscrew) and hold them up to the light. Seeds, eggshell and bits of plastic lodge in the jets. Clear them with a toothpick and rinse. Make sure each arm spins freely when reinstalled and that nothing on the racks blocks its path. A tall pan or cutting board on the bottom rack can stop the upper arm cold.
Water temperature
Detergent works properly only in hot water. The dishwasher heats water, but it starts with whatever comes from your water heater, and if that's the far side of a basement, the first gallon may be cold. Before starting a load, open the hot tap at the sink and let it run until it steams. If your dishwasher has a high-temperature or sanitize option, use it for heavily soiled loads.
Signs that point to a part failure
If the film is mineral and you've dealt with rinse aid, detergent and scale, and the grit keeps coming back after the filter and arms are clean, something inside the machine may not be doing its job. Signs include:
- •Very little water in the tub when you open the door mid-fill (carefully, and let it stop first). A failing inlet valve or a clogged inlet screen can starve the wash.
- •Dishes still cold and wet at the end, with no heat at all during the cycle. The heating element or its control may have failed.
- •A weak or unusual hum during the wash with little spraying sound. The circulation pump or its motor may be failing.
- •Standing water in the bottom after a cycle. That's a drain problem, which also leaves dirty water to redeposit.
- •An error code or a flashing light on the panel.
Before any inside work, turn off the dishwasher's power at the breaker or unplug it under the sink, and close the water supply valve.
When to have it looked at
If you've done the vinegar test, cleaned the filter, fixed the rinse aid and the problem continues, a technician can check fill volume, heater, pump and drain in one visit. They'll tell you what failed and what the repair will be before starting. If the dishwasher is old enough that a major part doesn't make sense, we'll say that too.
To book, call or schedule dishwasher repair online.