Most dishwasher complaints fall into a few groups: dishes that come out dirty or cloudy, water that stays in the bottom of the tub, leaks, and machines that will not start or will not dry. In the Las Vegas Valley, one factor touches almost all of them. The tap water is hard, drawn mostly from Lake Mead and the Colorado River, and it leaves mineral scale on everything it heats and sprays.
Understanding how that scale behaves will help you keep your dishwasher working longer and tell the difference between a maintenance problem and a broken part.
What hard water does inside a dishwasher
Dissolved minerals come out of the water as it heats and evaporates, leaving a chalky white film. In a dishwasher, that film shows up in several places:
- On glassware and dishes, as cloudiness or white spots
- In the spray arm holes, narrowing or blocking the jets
- On the heating element or in-line heater, reducing how well it heats
- On the inlet valve screen, slowing the fill
- Around the door gasket and tub, as crusty deposits
Scale also combines with food residue in the filter and sump, which is why a dishwasher here can lose cleaning power faster than the same model in a soft-water area.
Maintenance you can do yourself
Always turn the dishwasher off and let it cool before reaching into the tub. If you remove anything below the lower rack, watch for broken glass.
Clean the filter
Most modern dishwashers use a manual filter at the bottom of the tub, usually a cylinder that twists out with a flat mesh screen beneath it. Rinse both under warm water and use a soft brush for grease and scale. Many owners do not know their machine has a filter, and a clogged one is one of the most common causes of poor cleaning and standing water.
Clear the spray arms
Pop off the spray arms (most come off by hand or with a simple twist) and look through the holes. A toothpick will clear scale and debris. Do not enlarge the openings.
Use rinse aid
Rinse aid helps water sheet off dishes instead of drying in droplets, which matters a great deal with hard water. Keep the dispenser filled, and raise the setting if spots persist.
Run a descaling cycle
A dishwasher cleaner made for mineral deposits, or a citric acid product designed for dishwashers, can dissolve buildup. Run it in an empty machine on a hot cycle. Follow the product directions and your manual, because some manufacturers caution against certain cleaners.
Run the kitchen tap first
Before starting a cycle, run the kitchen faucet until the water is hot. The dishwasher then starts with hot water instead of the cool water sitting in the line.
Cloudy glasses: etching versus film
Not all cloudiness is scale. A mineral film can be removed: soak a glass in white vinegar, and if it comes clear, hard water is the cause. If the cloudiness stays, the glass may be etched, which is permanent surface damage. Etching is more often linked to too much detergent with soft water. A home water softener can change the right detergent dose, so adjust if you have one.
Water left in the bottom
A little moisture in the sump is normal. Standing water over the filter is not. Check these in order:
- Clean the filter and the sump area beneath it.
- If the dishwasher drains through a garbage disposal, run the disposal. A new disposal sometimes has a knockout plug that was never removed.
- Check the drain hose under the sink for kinks.
- Make sure the hose has a high loop or air gap so dirty sink water cannot flow back.
If the drain path is clear and water still sits in the tub, the drain pump, its impeller or a check valve may have failed.
Leaks
Leaks often come from a worn door gasket, a cracked spray arm, the wrong detergent producing too many suds, or a loose fitting under the machine. Turn off the water supply valve under the sink if the leak is significant. Water reaching cabinet floors or flooring is worth catching early, because damage spreads under the toe kick unseen.
When to call a technician
Stop and book a repair if you notice:
- No fill, or a slow fill after the inlet screen has been checked
- Water that does not heat, or dishes that never dry
- A burning or electrical smell, or a tripped breaker
- A humming sound with no water movement
- Persistent leaks from under the machine
- Error codes that return after a reset
These problems usually point to the inlet valve, heater, circulation or drain pump, float switch, door latch or control board. Most are contained repairs.
Repair or replace?
A dishwasher with a failed pump, valve, heater or latch is usually worth repairing, especially if the tub and racks are in good shape. Replacement starts to make sense when the tub itself is leaking, rust has spread through the racks, or several major parts are failing at once on an older machine.
Our technician diagnoses the dishwasher on-site and gives one price for parts and labor before any work begins. The repair we perform is covered by a 90-day parts and 30-day labor warranty.
Frequently asked questions
Why are my glasses cloudy even after a new detergent?
With hard water, cloudiness is usually mineral film. Make sure rinse aid is full, clean the filter and spray arms, and run a descaling cleaner. If a vinegar soak does not clear the glass, it may be etched, which cannot be reversed.
Do I need a water softener to keep my dishwasher working?
It is not required, but it helps. Without one, regular rinse aid, filter cleaning and periodic descaling keep scale under control. If you add a softener, you may need less detergent.
How often should I clean the dishwasher filter?
Many households should clean it every few weeks, and more often if you rarely pre-rinse dishes. If you notice gritty residue or standing water, check it right away.