Common Dishwasher Problems We Fix

Dishes come out dirty or covered in residue

The most common complaint we hear is that the dishwasher runs through a full cycle but the dishes are not clean. You might see food particles stuck to plates or a gritty film on your glassware. This defeats the purpose of the machine and wastes water and energy. In Natick hard water deposits can clog spray arm holes which significantly reduces the water pressure needed to blast away food.

Likely causes:

• Clogged spray arm holes restricting water flow
• Broken or blocked chopper blade assembly
• Degraded detergent dispenser not opening
• Inlet valve not letting enough water into the tub
• Circulation pump impeller is damaged or worn
• Hard water mineral buildup on internal components

How we diagnose it

We start by checking the water level inside the tub to ensure the unit is filling correctly. We inspect the spray arms for debris and verify they spin freely. We also examine the filter system and the food chopper for blockages. We test the wash motor to ensure it is generating enough pressure to reach the top rack.

What you can do right now

Remove the bottom rack and check the filter at the base of the tub for large debris like broken glass or bones. Check the holes in the spray arms and use a toothpick to clear any visible clogs. Run a cleaning cycle with a dishwasher cleaner to remove mineral buildup.

Dishwasher is not draining water

Opening your dishwasher to find a pool of grey standing water at the bottom is unpleasant and unsanitary. If the water does not drain it can lead to odors and potential leaks. This issue is often caused by a blockage in the drain path but it can also indicate a failure of the mechanical pump that pushes the water out to your sink drain or disposal.

Likely causes:

• Clogged drain filter or sump area
• Obstruction in the drain hose
• Failed drain pump motor
• Broken check valve allowing water to return
• Blockage in the garbage disposal knock out plug
• Electronic control not sending power to the pump

How we diagnose it

We listen to the pump during the drain cycle to hear if it is humming or grinding. We inspect the drain hose for kinks or clogs especially where it connects to the sink plumbing. We test the pump motor for continuity and inspect the impeller for damage. We also check the check valve to ensure dirty water is not backflowing into the machine.

What you can do right now

Clean out the filter basket at the bottom of the tub. Check your kitchen sink drain to make sure it is not clogged. If you have a garbage disposal run it to ensure it is clear. Make sure the drain hose loop under the sink is elevated to prevent backflow.

Water leaking onto the kitchen floor

A leaking dishwasher is a serious issue that can cause significant damage to your kitchen floor and cabinetry and the ceiling below. Leaks can be slow drips that go unnoticed for weeks or sudden puddles during a cycle. In older Natick homes with original wood flooring responding quickly to leaks is vital to preserving the home.

Likely causes:

• Worn or torn door gasket seal
• Loose hose connections or cracked hoses
• Leaking water inlet valve
• Cracked pump housing or tub
• Door alignment issues or bent hinges
• Using the wrong type of detergent causing suds

How we diagnose it

We remove the kickplate and use a flashlight to inspect underneath the unit while it runs a cycle. We look for water dripping from the pump or hoses or the float switch. We inspect the door seal for rips or compression issues. We also check the water inlet valve which can crack from water pressure spikes.

What you can do right now

Check the door seal for any food debris that might prevent a tight close. Verify you are using automatic dishwasher detergent and not regular dish soap which creates excessive suds that force water out. If the leak is active turn off the water supply valve under the sink.

Dishwasher will not start

It is frustrating when you load the dishwasher and press the start button but nothing happens. The control panel might be dark or the lights might be on but the cycle refuses to begin. This can be a simple safety feature engaging or a more complex electronic failure within the main control board.

Likely causes:

• Door latch or switch is broken
• Thermal fuse has blown due to overheating
• Main control board failure
• User interface or touchpad ribbon cable issues
• Tripped circuit breaker
• Child lock setting is activated

How we diagnose it

We test the door switch to ensure it signals the control board that the door is safely closed. We check for power at the junction box and inspect the thermal fuse for continuity. We examine the control board for burn marks or loose connections. We also test the user interface to see if the buttons are responding to touch.

What you can do right now

Check your home circuit breaker panel to see if the dishwasher breaker has tripped. Ensure the door is latched firmly. Look closely at the control panel to see if a “Control Lock” or “Child Lock” light is illuminated and try holding the button to unlock it.

Dishes are not drying

If your dishes are soaking wet at the end of the cycle you are forced to dry them by hand which adds time to your chores. Modern energy efficient dishwashers rely on residual heat and rinse aids more than the intense heating elements of the past but they should still produce dry dishes. Plastic items are naturally harder to dry but glass and ceramic should come out dry.

Likely causes:

• Burned out heating element
• Malfunctioning vent fan assembly
• Rinse aid dispenser is empty or broken
• High limit thermostat cut off the heat
• Control board relay failure
• Loading issues preventing airflow

How we diagnose it

We test the heating element for continuity to see if the electrical path is broken. We inspect the high limit thermostat which is a safety device that cuts power if the unit gets too hot. We check the rinse aid dispenser mechanism. We also verify that the vent fan opens and runs during the drying cycle to exhaust humid air.

What you can do right now

Refill the rinse aid dispenser as this is essential for drying in modern machines. Use the “Heated Dry” or “Sanitize” option if available. Try opening the door slightly right after the cycle ends to let the steam escape which helps flash dry the dishes.

Dishwasher is making loud or strange noises

While no dishwasher is silent it should run with a consistent hum and the sound of swishing water. If you hear grinding or thumping or high pitched squealing it indicates a mechanical problem. Ignoring these sounds often leads to a complete failure of the motor or pump components.

Likely causes:

• Debris stuck in the chopper blade or pump impeller
• Worn wash motor bearings
• Drain pump failure
• Spray arm hitting dishes or the rack
• Water hammer in the inlet pipes
• Loose mounting brackets allowing vibration

How we diagnose it

We identify when in the cycle the noise occurs to determine if it is the drain pump or the wash motor. We inspect the pump housing for foreign objects like fruit pits or glass shards. We spin the spray arms by hand to check for clearance. We also check the leveling legs to ensure the unit is stable.

What you can do right now

Open the door and spin the spray arms to make sure they are not hitting a tall plate or a utensil sticking out of the basket. Check the bottom of the tub for any loose items like spoons or bones that might be rattling around.

Cycle runs too long

If your dishwasher takes four or five hours to complete a cycle it is often a sign that it is struggling to heat the water or sense the soil level. While energy efficient cycles are longer than older machines excessive run times indicate a malfunction. This wastes electricity and keeps you waiting for clean dishes.

Likely causes:

• Heating element is weak or broken
• Thermostat or temperature sensor failure
• Soil sensor is dirty or malfunctioning
• Cold water entering the unit excessively
• Clogged filters restricting water circulation
• Control board timer failure

How we diagnose it

We check the temperature of the water inside the tub. If the water is not reaching the target temperature the cycle will extend indefinitely while it waits. We test the heating element and the thermistor. We also clean and test the optical soil sensor to ensure it can see when the water is clean.

What you can do right now

Run the hot water at your kitchen sink until it is hot before starting the dishwasher. This primes the line so the machine starts with hot water. Clean the sensors inside the tub with a soft cloth and vinegar to remove any film.

Soap dispenser does not open

Opening the door to find a dissolving detergent pod or a clump of powder still in the cup means your dishes were just rinsed with water. The dispenser operates on a spring and latch mechanism triggered by the control board or a wax motor. If this timing is off or the mechanism is jammed the soap never enters the wash.

Likely causes:

• Broken dispenser spring or latch
• Wax motor failure
• Dishes blocking the dispenser door
• Detergent residue gumming up the slide
• Control board signal failure
• Warped dispenser door

How we diagnose it

We inspect the dispenser assembly for physical damage or sticky residue. We test the actuator or wax motor that triggers the door to open. We also check the wiring harness connecting the dispenser to the main control board.

What you can do right now

Make sure the dispenser cup is dry before adding powder. Check that no tall plates or cutting boards are placed in the lower rack directly in front of the dispenser door which would block it from flipping open.