Dishwasher Not Cleaning Dishes Well? What the Residue Tells You

Quick answer

Look at what is left on the dishes first: each kind of residue points to a different cause. Food bits usually mean the spray can’t reach the dishes: crowded loading, a blocked spray arm or clogged holes, or a dirty filter. Sandy grit often means the water isn’t hot enough to dissolve the detergent, and white film or spots usually come from hard water, the wrong amount of detergent, or an empty rinse aid dispenser. Start by spinning the spray arms by hand, checking the filter, and running the kitchen faucet hot before each cycle.

Match the residue to the cause

Pull out a few of the dirtiest items and look at them in good light. Rub a spot with a fingertip: is it food, grit, a film, or dried drops?

What you see	Causes the manufacturers list	Check first
Food bits stuck on dishes	Crowded dishes or a blocked spray arm, clogged spray arm holes, a dirty or loose filter, a cycle too light for the load (Bosch, GE, Whirlpool, LG)	Loading, spray arms, filter, cycle
Sandy or gritty feel	Water not hot enough to dissolve the detergent (GE); a filter that needs cleaning (Bosch)	Hot water, filter
White film that wipes off with vinegar or lemon juice	Hard water minerals (Samsung, KitchenAid, Cascade); too little detergent (Frigidaire, Bosch)	Hard water, detergent, rinse aid
Cloudy film that will not wipe off	Etching, which is permanent: too much detergent, very soft water, long hot cycles (KitchenAid, Samsung, Frigidaire)	Detergent amount, water hardness
Water spots or streaks	Spots: no rinse aid or hard water (GE, Bosch). Streaks: rinse aid set too high (Bosch)	Rinse aid
Greasy film, or lipstick and tea marks	A dirty machine (Finish); wash temperature too low or too little detergent (Bosch)	Filter, spray arms, hot water, detergent
Detergent or a pod left in the dispenser	Door blocked by dishes, dispenser wet when filled, old or clumped detergent, a tab in a quick cycle (Bosch, Frigidaire, Cascade)	Loading near the dispenser, detergent

Causes vary by model. Your owner's manual has a troubleshooting table for your dishwasher. Source: GE Appliances, Bosch, Whirlpool, KitchenAid, LG, Samsung, Frigidaire, Cascade, and Finish pages and manuals listed below

If detergent is left in the dispenser, fix that first. Until the detergent dispenses and dissolves, Samsung says, the dishwasher will struggle to clean anything.

1. Check how the dishes are loaded

Every appliance maker cited here lists loading as a cause.

• Spin the spray arms by hand. Before a cycle, give the middle arm a turn, as Whirlpool and KitchenAid suggest, and move any dishes it catches on. Tall items can block the arms (Bosch), so adjust the rack height or move dishes that touch them (LG).
• Give each item room. Overloading restricts water circulation (Whirlpool), and Bosch’s SHX78CM5N manual says items should not touch. Don’t nest bowls or overlap plates.
• Face the dirty side toward the spray. Angle soiled surfaces down and inward toward the spray arms (Whirlpool). Stand plates upright and load cups and bowls upside down (LG).
• Keep the detergent door clear. If water can’t reach the dispenser, the detergent may release too late to dissolve properly, KitchenAid explains. Small utensils and large pot handles can both get in the way (Cascade).
• Set the upper rack level. The same Bosch manual blames food left on dishes on an upper rack set higher on one side than the other.

2. Clear the spray arm holes

Limescale and debris can block the holes (nozzles) in the spray arms, so Bosch’s manual recommends cleaning them regularly.

1. Turn off the power and remove the spray arms the way your manual shows. On the Bosch SHX78CM5N, for example, the upper arm unscrews and the lower arm lifts straight up.
2. Rinse each arm under running water to see which holes are blocked.
3. Loosen debris with a toothpick (Bosch, Cascade) or a paper clip or tweezers (GE). Go gently: GE warns that damaged holes hurt wash performance.
4. Reinstall the arms. On that Bosch model, push the lower arm down until it clicks and screw the upper arm firmly in place.

3. Check the filter, and make sure it’s locked in

Too much food can clog the filters and reduce wash performance, and GE’s wash performance page says to clean its removable Fine and Ultra Fine filters once a month. An older Bosch manual (SHEM63 models) says to clean the filter when cleaning drops off or a gritty film forms on dishes, about 3 to 6 times a year for light to average use and 8 to 12 for heavy use.

A filter that isn’t seated causes trouble too: Bosch’s SHX78CM5N manual lists filters not inserted correctly or not twisted into place as a cause of food left on dishes.

For each brand’s filter location, steps, and schedule, see how to clean a dishwasher filter.

4. Make sure hot water reaches the dishwasher

Detergent needs hot water to dissolve and activate. GE says the water coming into the dishwasher should be at least 120°F, and that sandy grit on dishes typically comes from water that isn’t hot enough. Cascade gives the same minimum.

To check it, measure the hot water at the kitchen sink with a candy or meat thermometer, as GE suggests.

• Run the kitchen faucet until the water is hot, then start the dishwasher. GE, Cascade, and Bosch all recommend this.
• Don’t compete for hot water. Avoid running the dishwasher during or right after a shower, bath, or laundry cycle (GE).
• Use the heat options your model has, such as GE’s Hot Start, Added Heat, or Wash Heat Boost, or Whirlpool’s high-temperature wash.
• Confirm the hot water connection. GE says none of its dishwashers can heat cold water enough to wash well, so they must be on the hot water line.

If the sink water never reaches 120°F, the water heater may be set low. CPSC recommends 120°F for water heaters to reduce scald risk, which matches GE’s minimum. If the water is barely warm at every faucet, see Electric Water Heater Not Heating?

5. Use the right detergent, in the right amount

Only automatic dishwasher detergent. Dish soap makes suds, which can push water out of the dishwasher and cause leaks or poor washing, Whirlpool explains.

Fresh and dry. Store detergent closed tight in a cool, dry place and add it just before the cycle (Whirlpool). Damp or caked detergent may not dissolve (Frigidaire).

Pods and tablets. Whirlpool and KitchenAid recommend quality pre-measured tablets or packs, saying they reduce white film better than powder, liquid, or gel. Put one in the main compartment and close the lid. Don’t unwrap it, handle it with dry hands, and make sure the dispenser is dry (Cascade). Bosch’s SHX78CM5N manual adds that a tab may not dissolve in a quick cycle, and one standing upright can jam the lid, so lay it crosswise.

Liquid and powder. LG says liquid detergent may reduce cleaning performance, while Frigidaire allows powder, liquid, or tablets.

How much. For powder or gel, the amount depends on water hardness. Too little can mean poor cleaning and hard water film or spots, while too much in soft water can etch glassware (Frigidaire). Charts differ by model, so check yours. One Frigidaire example:

Water hardness	Detergent	Dispenser level
Soft (0 to 3 grains per gallon)	4 teaspoons	First line
Medium (4 to 8 grains)	6 teaspoons	Second line
Hard (9 to 12 grains)	8 teaspoons	Full

For powder or gel. For tablets, Frigidaire says to use one in the main wash cup. Source: Frigidaire, Dishwasher - Dispenser and Detergents Guide

Don’t overfill the cup. KitchenAid warns that the latch can bind so the dispenser door doesn’t open.

6. Fill and set the rinse aid

Rinse aid makes water sheet off the dishes, which prevents water spots and improves washing and drying (GE). Whirlpool adds that it controls hard water buildup.

• Fill it even if your pods include rinse aid. Rinse aid inside a combination detergent has limited effect, and a separate one generally works better (Bosch’s SHX78CM5N manual).
• Match the setting to the problem. A higher setting reduces water spots, and a lower one reduces streaks (Bosch).

7. Test for hard water, and treat it

Film or etching? Wipe a filmy glass, inside and out, with lemon juice or white vinegar (Samsung’s test). If the film comes off, it’s hard water. If not, the glass is etched. Etching is permanent, Samsung and KitchenAid say, so the goal is to stop it from spreading: use less detergent and make sure your water isn’t overly soft.

Find your hardness. Your water company, a water softener company, or your county extension agent can tell you, Frigidaire says.

When to soften. Whirlpool and KitchenAid recommend a water softener at 15 grains per gallon or harder. Samsung cautions that water softer than 7 grains per gallon risks etching. With a built-in softener, raise its setting when limescale builds up (Bosch).

Detergent matters too. Phosphate-free detergents can leave a white film, most often in hard water areas, according to GE.

To remove film that’s already there, use one method at a time:

• Vinegar (Whirlpool): 2 cups of white vinegar in a glass or dishwasher-safe measuring cup on the bottom rack, a full cycle with no detergent, air dry. Vinegar is an acid, and Whirlpool warns that using it too often could damage the dishwasher.
• Vinegar with dishes inside (Cascade): non-metal items only, then a second wash with detergent. Clean metal by hand.
• Citric acid (GE): in the detergent cup, no detergent, with silverware and other metal items left out.
• A dishwasher cleaner product, which Whirlpool, GE, and Finish all mention.

8. Pick the right cycle, and scrape instead of rinsing

• Short cycles have limits. The Rinse cycle won’t clean dishes, and Quick Wash and 30-minute cycles may not clean heavily soiled loads (Frigidaire).
• Check zone settings. On models with Wash Zones (an upper-rack-only or lower-rack-only option), GE says to leave that feature off.
• Scrape, don’t rinse. Detergent needs small food particles to cling to, Bosch says, and heavily pre-rinsed dishes can lead the soil sensors to pick a lighter cycle. Samsung also advises against pre-rinsing. LG’s one exception: soak burnt pots or baked-on egg for about an hour and rinse them before loading.

If the dishwasher may not be getting enough water

• Try the cup test. Set a large mug, open end up, on the top rack. Cascade says it should be full when the cycle ends.
• Check the supply valve. It must be fully open, and a flood-prevention device installed incorrectly can stop water from reaching the dishwasher (Whirlpool).
• Standing water in the tub when the dishwasher is off points to a drain problem. See Dishwasher Not Draining.

How to keep dishes coming out clean

• Scrape food off, but skip the full pre-rinse.
• Keep the filter clean and the rinse aid full, and start each load with hot water at the tap.
• Clean the dishwasher itself on your maker’s schedule: about every 30 days for Whirlpool, or every 24 cycles for Samsung (which says once a month is usually enough). Each brand’s cleaning cycle is in Dishwasher Smells Bad?.