Dishwasher Hums, but No Water? Here’s What To Do

July 19, 2023
Dishwasher Repair

If your dishwasher is making its usual humming noise but not filling with water, you may be wondering what could be going on. Before you call a professional repair person or throw in the towel and buy a new dishwasher, take a deep breath and read on. You might find that the solution to your dishwasher issue is simple. Here we discuss several possible causes for no water coming out of your dishwasher and provide helpful tips to try fixing it.

1. Prime the Pump Motor

*This step only applies if the dishwasher hasn’t been used in a week or more.*

The dishwasher is a modern-day convenience that quickly became a staple in many households. It not only saves time and energy, but it also ensures sparkling clean dishes with just the touch of a button.

However, for this kitchen appliance to function correctly, it requires a pump motor. This essential component allows the pump to draw water into the dishwasher’s washing chamber and wash the dishes.

The pump motor is designed to be used frequently and is meant to work in wet conditions.

If your dishwasher hasn’t been used in a week or longer, the pump seals can dry out or become sticky, making it difficult for water to flow.

Fortunately, you can prime the pump pretty easily.

First, ensure the dishwasher is clear of any dishes or standing water.

Then, dissolve 3–4 ounces of citric acid in a quart of hot water. Citric acid is usually found in the canning section of your grocery store.

If citric acid isn’t available, you can substitute a cup of white vinegar. However, it is less effective than citric acid.

Pour the citric acid solution into the drain area of your dishwasher, usually at the rear right of the tub. Let the solution stand for 15–30 minutes.

Try to start the dishwasher again. If the dishwasher doesn’t start, then the problem lies deeper in the dishwasher.

*For the following steps, you’ll need to partly disassemble the dishwasher. If you’re not comfortable with DIY work, you can call a repair professional.*

2. Check the Water Supply Line

When checking a dishwasher, one thing you don’t want to overlook is the water supply line. It’s the way your dishwasher receives water. It’s also one of the most common dishwasher components to fail. But fortunately, it’s also the easiest to replace.

First, make sure the dishwasher is turned off. Unplug the dishwasher, or flip the circuit breaker switch associated with the dishwasher.

Next, to turn off the water valve using the switch under the sink. While there, place a towel under the water supply line and disconnect the water supply line from under the sink.

Next, remove the kickplate at the base of the dishwasher. This usually detaches with a slight tug. After that, remove the baseplate using a screwdriver. Here, beneath the dishwasher, you’ll find the other end of the water supply line attached to the water inlet valve.

Disconnect the water line.

Unscrew the filter (a small mesh screen on one end of the water line, and soak it in a bath of soapy water.

Run water through the supply line using the sink to clear out debris. Then visually look down the line for any buildup of calcium deposits; these will be hard, white obstructions. Soak the supply line in a mixture of equal amounts of water and vinegar for at least 30 minutes to soften any calcium deposits.

Clear out any remaining deposits from the supply line using a pipe-cleaning snake.

Rinse out any debris and vinegar, and then reattach the filter to the water supply line. Reattach the water supply line to the sink and the dishwasher and turn the water back on. Plug the dishwasher back in to restore power.

Run a short test cycle to see if the dishwasher fills. If it begins to fill, turn off the dishwasher and replace the baseplate and kickplate.

If it doesn’t begin to fill with water after 90 seconds, turn off the dishwasher and check the inlet valve. This will be the next part to clean.

3. Clean the Inlet Valve

To access the inlet valve, follow the steps above until you get to the inlet valve. Then, disconnect it from the water supply line and dishwasher supply line. You’ll need a pair of pliers to undo the clamps.

After removing the inlet valve, follow the cleaning steps above, using a narrow tool to clean the inside of any calcium deposits after giving the inlet valve a vinegar bath.

Replace the inlet valve.

If the dishwasher still doesn’t work properly after testing, it’s time to check the float.

4. Check the Float

The float is a small mechanism that helps regulate water levels in the dishwasher. If it’s not functioning correctly, the dishwasher may be unable to move from one cycle to the next. Checking the float is a simple troubleshooting step.

Open the dishwasher door and locate the float; it’s a small, circular object on the tub of the dishwasher.

Try to move the float up and down with your hand. If the float moves easily, then this is not your issue. Regardless,  run your dishwasher on a short test cycle. If the float struggles to move, then the issue is your float switch.

5. Inspect the Float Switch

Follow the steps above to disconnect the power and turn off the water. Remove the kickplate and baseplate, as mentioned above, to access the float switch.

The float switch is a circular object with wings directly beneath the float. Disconnect the float switch from any wires, and use a multimeter to test for continuity.

If you detect continuity, the switch is fine and you need to call a repair technician as the issue is more complicated.

If you don’t detect continuity, the float switch must be replaced. This is an extensive repair and should be done by a repair professional.

All in all, ensuring your dishwasher fills with water is relatively easy. A few simple steps, such as priming the pump motor after a period of non-usage, disconnecting and cleaning the water supply line and water inlet valve, and inspecting the float and float switch can mean all the difference between a machine that doesn’t clean dishes properly and one that runs correctly.

If you attempted these basic repairs and still have problems with your dishwasher not filling, it could be time to consult an appliance repair professional.


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