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Why won’t my dishwasher fill with water? Causes and fixes

By: Reliable Parts • August 2026

A dishwasher that won’t fill is most often caused by a closed supply valve under the sink, a failed water inlet valve, or a float stuck raised telling the control the tub is already full. A dishwasher that hums but stays dry has an inlet valve problem; a silent one may be stopping at the float or door switch. Identify your dishwasher’s model number to order the correct replacement parts.

Need step-by-step instructions for your specific brand and model? Visit our DIY Repair Guide and filter by appliance and brand.

Safety information

Disconnect power at the breaker and shut off the water supply before working at the inlet valve or float switch - most dishwashers are hardwired, and the valve sits beside the junction box. Have towels ready when opening the supply fitting; the line holds pressurized water. Confirm connections are dry before restoring power.

Most common causes

  1. Supply valve closed or clogged — the shutoff under the sink was bumped closed, or an old saddle valve has scaled nearly shut; the first thing to check.
  2. Failed water inlet valve — the solenoid no longer opens, or the valve’s screen is packed with sediment; the most common part failure.
  3. Stuck float — debris under the float dome holds it raised, and the control refuses to fill a tub it believes is full.
  4. Kinked supply line — the braided or copper line crushed against the cabinet during storage of items under the sink.
  5. Door not fully latched — the control won’t start a fill without a latched-door signal; a marginal latch stops everything silently.
  6. Failed float switch or control — the switch under the float fails in the tripped state, or the control never energizes the valve.

Step-by-step diagnosis

  1. Confirm the supply valve under the sink is fully open, and check the line for kinks where stored items press against it. If the valve is an old saddle-style tap, treat it as suspect - they scale internally and choke flow; replacing one with a quarter-turn valve is a worthwhile plumbing fix.
  2. Check the float in the tub floor. Lift and release it - it should move freely and click its switch. Clear food debris and glass from under the float dome, and confirm nothing in the sump area props it up.
  3. Listen at the start of a cycle. A hum with no water is the inlet valve energizing but not passing water - screen or valve. Silence points earlier in the chain: door latch, float switch, or control never commanding the fill.
  4. Shut off the water, disconnect power, remove the kick panel, and disconnect the supply line at the inlet valve. Clean the small filter screen in the valve inlet - sediment here is common after any plumbing work in the house - and check flow from the supply line into a pan before reconnecting.
  5. Test the inlet valve solenoid for continuity; an open coil confirms replacement. A valve with a good coil, clean screen, and confirmed supply that still passes no water when energized has failed mechanically - replace it rather than attempting repair.
  6. Test the float switch under the tub, directly below the float. With power off, check continuity as you raise and lower the float - a switch stuck open in the raised state blocks filling permanently. Replace a failed switch.
  7. Check the door latch and control last. Confirm the door clicks firmly and the latch microswitches test good; then, if the valve, float, and latch all pass, verify with the wiring diagram whether the control sends voltage to the valve at fill time - no voltage means the control or timer is the fault.

Replacement parts to consider

Common parts for a no-fill dishwasher: water inlet valve, float and float switch, supply line, door latch assembly, control board or timer. Enter your dishwasher’s model number on reliableparts.com for the exact parts for your specific model.

Related FAQs

Why does my dishwasher hum but no water comes in?

The hum is the inlet valve solenoid energizing - so the control and door latch are doing their jobs, and the blockage is at the valve: a sediment-packed inlet screen, a scaled-shut supply valve, or a mechanically failed inlet valve. Clean the screen first; it’s the five-minute fix that usually wins.

Where is the float in a dishwasher and what does it do?

It’s the small dome or cylinder on the tub floor, usually front-left. As water rises the float rises with it, and at the proper level it trips a switch that closes the inlet valve - the overfill safeguard. Stuck up, it reports a full tub before any water arrives, and the dishwasher never fills.

Why won’t my dishwasher fill after I did plumbing work?

Any work on household plumbing sends scale and sediment downstream, and the dishwasher inlet valve’s fine screen is where it lands. Shut off the supply, disconnect the line at the valve, and clean the screen. Also confirm the shutoff under the sink was reopened fully - the most common post-plumbing miss.

Can hot water supply problems stop a dishwasher from filling?

If the dishwasher’s dedicated shutoff (usually teed off the hot line under the sink) is closed or scaled, yes - the machine has no other source. Confirm hot water flows at the sink faucet, then check the dishwasher’s own valve and line. The machine doesn’t care about temperature to fill; it cares about flow.

How much does a dishwasher inlet valve cost to replace?

Inlet valves typically run $20-60, and replacement is one of the more approachable dishwasher repairs: power and water off, kick panel off, transfer the supply fitting, outlet hose, and wiring plug to the new valve. Budget under an hour. Professional replacement generally runs $125-250.