Clean the Filter First
Most dishwashers have a filter at the bottom of the tub that traps food particles. If it is clogged, dirty water recirculates and dishes come out gritty. Remove the filter following the maker's instructions, rinse it under running water, and check the sump area underneath for trapped food or debris. Do this regularly, not only when dishes look dirty.
While the filter is out, check the drain area for standing water. A small amount of water in the bottom is normal on many models, but a deep pool after a full cycle points to a drain problem.
Check the Spray Arms
Spray arms need to spin freely and spray through every hole. Food, limescale, and debris can block the holes, so water never reaches part of the load. Remove the arms if the maker allows it, rinse them, and clear blocked holes with a soft pick. Spin each arm by hand: if it catches on a rack or a tall item, loading is part of the problem.
Loading matters too. Tall items that block the spray arms, bowls facing the wrong way, and a rack packed so tightly that water cannot circulate will all leave dishes dirty, even on a healthy machine.
Water, Heat, and Detergent
Dishwashers need hot enough water to clean and dry. If the water entering the machine is cool, run the hot tap at the sink until it runs hot before starting the dishwasher. Use the amount of detergent the maker recommends for your water hardness: too little leaves food behind, and too much can leave a film.
Hard water can leave white cloudiness on glasses. That is often a water-softening or rinse-aid issue rather than a fault. If cloudiness appears suddenly, or only on some items, note when it started and what changed, and tell us when you call.
When It Needs a Technician
If cleaning the filter and spray arms does not help, the circulation pump, water inlet valve, heating element, or drain pump may be at fault. A dishwasher that will not fill, will not drain, leaks, or makes a loud grinding noise needs diagnosis rather than another round of cleaning products.
Stop using the machine if it leaks, and shut off its water supply if you can reach the valve safely. When you call, tell us the brand and model number, whether water stands in the bottom after a cycle, and whether the problem affects every load or only some. See our dishwasher repair page for what a visit includes.