Start with the quick checks
When a dishwasher will not fill, the cause is often simple. Before looking at any parts, check these:
- Power: Is the dishwasher getting power? Check that the household circuit breaker has not tripped and the control panel responds.
- Door: Close the door firmly. Most dishwashers will not run, or will not fill, if they think the door is open.
- Cycle: Confirm a cycle has actually been started. Some models need you to press Start after closing the door, and a flashing Start or Resume light can mean the machine is waiting.
- Water in the tub: If there is already standing water, you may have a drain problem rather than a fill problem. See the section on water that will not drain below.
If none of these solve it, move on to the fill path: the supply valve, door latch, float and inlet valve.
Dishwasher not filling with water
Most guides point to the same four common causes: a closed supply valve, a door latch or switch problem, a stuck float, or a faulty water inlet valve. Work through them in that order, simplest first.
Supply valve and supply line
The dishwasher’s water shut-off valve is usually under the kitchen sink. If it was closed during a plumbing job, the machine will not fill. Open it fully, and check that the supply line is not kinked or crushed where it passes behind the unit.
Door latch and switch
If the door does not latch squarely, the machine may not start filling. Check that nothing is blocking the door, such as a rack, a utensil or a tall item. Listen for a click when you close it. If the latch looks broken or the door does not catch, the latch assembly may need replacing. On integrated machines, a heavy cabinet panel is a common cause of door and latch trouble (see integrated dishwasher problems). The latch is wired into the control circuit, so leave testing and replacement to a qualified technician unless you are experienced and have disconnected power at the breaker.
Float switch
Many dishwashers have a float inside the tub that rises with the water level. If it sticks in the raised position, the machine can behave as if it is already full and refuse to take in water. With the power off, lift the float gently and make sure it moves freely up and down, and clear away any residue around it. If it moves freely but the problem continues, the float switch itself may be faulty, which is a job for a technician.
Water inlet valve and screen
The inlet valve opens to let water in. Mineral deposits or debris can clog its small screen, and the valve’s electrical coil can also fail. Reaching the valve usually means turning off the water, switching off power at the breaker and removing the lower access panel. If you are not comfortable working with mains-powered components, stop here and call a professional. A valve that is clean but does not open when the machine calls for water generally needs to be replaced.
Dishwasher humming but not working
A humming sound with no water movement can have several causes, so treat it as a clue, not a diagnosis. It might come from the inlet valve trying to open, the drain pump or the circulation pump straining against a blockage, or a motor that is struggling. Check first that the water supply is on and that the filter and sump are not blocked. If the hum continues, switch the machine off at the breaker and have it looked at, since a motor left to hum can overheat.
Dishwasher will not start
If nothing happens at all (no lights, no sounds), check the breaker and whether the machine is on a switched outlet or a dedicated circuit. Some models lock the controls: check the manual for a control-lock or child-lock setting. If a specific brand such as Blomberg will not start, the model’s manual is the best source for its lock, delay-start and error behavior. If lights are on but the cycle will not begin, return to the door latch checks above.
Is there a reset button?
Most dishwashers do not have a dedicated reset button. Many models can be reset by cancelling the cycle with the panel buttons (the method varies by brand, so check the manual), or by switching power off at the breaker for a few minutes and then back on. This can clear a minor control glitch, but it will not fix a failed part. If the same fault returns, move on to diagnosis instead of resetting repeatedly.
Water in the tub that will not drain
If the machine has water at the bottom after a cycle, the problem is drainage, not filling. Check the filter at the base of the tub and the drain hose for clogs or kinks. For Bosch machines, our Bosch dishwasher drainage problems guide goes through the filter, pump cover and hose in detail, and the same general approach applies to many other brands.
Dishes still wet at the end
If the machine fills and washes but dishes come out wet, the drying setting may be the issue rather than a fault. See our explanation of heat dry versus extended dry for what each option does and how to improve drying.
When to call a professional
Handling water and mains electricity together calls for caution. Always switch the dishwasher off at the breaker before touching anything inside it or behind its lower panel, and shut off the water when working near the inlet valve. Call a qualified technician if:
- you need to test or replace electrical parts such as the latch, float switch, inlet valve, control board or pump motor
- you smell burning or see scorching, melted wiring or signs of leaking onto electrical parts
- the breaker trips repeatedly when the dishwasher runs
- you are unsure about any step
How long does a dishwasher last?
Lifespans vary with the brand, water quality and how often the machine is used. A figure often quoted is roughly a decade, but this is only a rough guide. If the machine is older and needs a major repair, compare the repair cost with the price of a replacement, and ask a technician for advice.
FAQ
Why won’t my dishwasher fill with water? Common causes are a closed supply valve, a door that is not latched, a stuck float or a faulty inlet valve.
Why is my dishwasher humming? It may be a pump or valve working against a blockage or failing. Check the supply and filter, and call a technician if it continues.
Does my dishwasher have a reset button? Most do not. Cancelling the cycle or turning power off at the breaker briefly can reset the controls on many models. Check your manual.