If your glasses come out of the dishwasher with a cloudy haze, or plates have a gritty white film, the problem may not be the dishwasher at all. Much of Los Angeles gets moderately hard to hard water, and it varies quite a bit depending on your neighborhood and water supplier. The minerals that make water hard leave deposits on dishes and inside the machine. Other times, the haze is a sign of a real mechanical fault. This guide helps you tell them apart.
Is it film or etching?
These look similar but have completely different causes.
- •Mineral film is a deposit sitting on top of the glass. It comes from hard water and can be removed.
- •Etching is permanent damage to the glass surface itself. It usually comes from too much detergent in soft water, or very hot water and aggressive detergents over time.
The vinegar test: soak a cloudy glass in white vinegar for five minutes, then rinse it. If it comes out clear, you're dealing with mineral film. If it's still cloudy, it's etched, and no cleaner will fix it — but you can stop it from getting worse by using less detergent.
Find out what your water is like
Your water utility publishes an annual water quality report, sometimes called a Consumer Confidence Report, which lists water hardness. Depending on where you live, that might come from LADWP, a city utility like Pasadena, Glendale or Burbank, or another local water supplier. Hardness can also change seasonally depending on which sources are being used. Knowing your water's hardness helps you set detergent and rinse aid correctly.
Getting rid of hard-water film
Use rinse aid
Rinse aid isn't an optional extra in hard water. It helps water sheet off dishes instead of drying into spots. Fill the dispenser, and if your dishwasher has an adjustable rinse aid setting, try a higher one.
Match detergent to your water
Harder water generally needs a detergent that's formulated to handle it. Pods and tablets are pre-measured, so if you're seeing film, you might try a different product rather than using more. If you're seeing etching, try using less.
Check the built-in softener, if you have one
A few European-built dishwashers, including some Bosch models, have a built-in softener that uses dishwasher salt. Most dishwashers sold in the US don't, so don't worry if you can't find one. If you do have one, an empty salt reservoir or the wrong hardness setting can explain spotting on its own; our Bosch dishwasher guide explains how to set it.
Clean out the scale
Run an empty cycle with a dishwasher cleaner designed to remove mineral build-up, or follow your manufacturer's recommendation. Scale builds up on spray arms, the filter, the heating element and the door, and it reduces cleaning performance over time.
Run the hot water first
Before starting the dishwasher, run the kitchen tap until the water comes out hot. That way, the first fill uses hot water rather than whatever was sitting in the pipes, which helps detergent work properly.
When the dishwasher itself is the problem
Hard water explains film. It doesn't explain food left stuck on dishes, dishes that are cold and wet at the end of a cycle, or a dishwasher that sounds different than it used to. Those point to mechanical issues.
The filter
Most modern dishwashers have a manual-clean filter at the bottom of the tub. When it's clogged, dirty water recirculates and redeposits grit onto clean dishes. Twist it out, rinse it under the tap, scrub gently with a soft brush, and put it back firmly.
Spray arms
Take the spray arms off (most unclip or unscrew) and look at the holes. Mineral scale and bits of food can block them. Clear them with a toothpick, and soak scaled arms in vinegar. Make sure the arms spin freely once reinstalled, and that nothing in the racks is blocking them.
Water temperature and heating
If dishes are coming out cold, or cycles take far longer than they used to, the dishwasher may not be heating the water properly. Scale on the heating element can reduce its effectiveness, and a failed heater or temperature sensor will stop it heating entirely.
Water supply
Mineral build-up on the small screen inside the water inlet valve can restrict the flow of water into the dishwasher. If the tub seems to fill less than it used to, that's worth having checked.
Signs you need a technician
- •Dishes are still dirty after you've cleaned the filter and spray arms
- •The dishwasher isn't filling, or fills very slowly
- •Dishes are cold at the end of a hot cycle
- •Water is left standing in the bottom after a cycle — see our separate guide to a dishwasher that won't drain
- •Leaks around the door or under the machine
- •Error codes that keep coming back
How a technician approaches it
A technician will usually check the water supply and fill volume, the wash motor and spray pressure, and the heater and temperature sensor. They'll also look at the filter and sump for build-up and check the inlet valve for scale. On built-in models, they'll also check the door seal and whether water has been reaching the cabinets or floor. We work on most major dishwasher brands; there's more on our dishwasher repair page.
Protect the cabinets around it
A dishwasher sits inside cabinetry, so a slow leak can go unnoticed for weeks. Check the floor in front of the dishwasher and the bottom of the neighboring cabinets now and then. Swelling or soft spots mean water has been escaping. In multi-unit buildings, a leak can reach the unit below, so deal with it promptly and let your building manager know.
Maintenance that makes a difference in hard water
- •Clean the filter every few weeks.
- •Keep the rinse aid dispenser topped up.
- •Run a descaling cycle periodically, following the manufacturer's advice.
- •Wipe the door gasket to keep it sealing properly.
- •Scrape (don't pre-rinse) dishes — modern detergents need some food soil to work against.
Frequently asked questions
Will a whole-house water softener fix cloudy dishes?
It can reduce hard-water film, but it's a larger decision with its own maintenance and cost. It's worth researching separately. Many people get good results just with rinse aid and the right detergent.
Why are my plastic containers always wet?
Plastic doesn't hold heat the way glass and ceramic do, so water doesn't evaporate as quickly from it. Rinse aid helps, but some dampness on plastic is normal.
Can hard water damage my dishwasher?
Over time, scale can build up on the heating element, the inlet valve and the spray arms, which affects performance. Regular cleaning and descaling helps it last longer.