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Dishwasher Float switch and leak sensor: What It Does and Signs It's Failing

Two related safety parts. The overfill float is the plastic dome or tube in a front corner of the tub; if water rises too high it lifts and trips a switch that stops the fill. Many machines also have a leak sensor or float in the base pan under the tub that reacts to water that has escaped.

How it works

As the float rises it pushes on a microswitch, and the control shuts the inlet valve and often runs the drain pump. The base-pan float works the same way but triggers a leak error and blocks the machine from running.

Signs it is failing

• No fill at all because a float is stuck up or something is wedged under it
• Overfilling and water on the floor
• The drain pump running on its own
• Leak or drip-tray codes that come back with no visible leak

Overfill, leak-protection and drip-tray codes involve these switches, but they usually mean real water is somewhere it shouldn't be, so find the leak before suspecting the switch. Whirlpool adds that a float switch knocked unplugged during installation can set its drip-tray code.

Can you replace it yourself?

Check that the tub float moves up and down freely and nothing is caught under it; GE suggests tapping the float cover to free a stuck float. If the base pan has water in it, find the source first, and only tip the machine to empty it if your maker's instructions say to. Never tape, prop or jumper a float switch to get the machine running again.

Buying the right part

Floats and switches differ by model. Order the OEM part by the full model number, and check the float itself for cracks when you replace the switch.

Error codes linked to the float switch and leak sensor

• E15Water detected in the base (leak protection)Bosch
• i30Leak or overflow in the base panFrigidaire
• C4Overfill float stuck or sump cloggedGE
• C5Drain time too short (underfill)GE
• LEAK DETECTEDLeak sensor found waterGE
• F8E4Water found in the drip trayKitchenAid
• F6E4Float switch errorKitchenAid
• AE / E1Leak detected in the baseLG
• F70Waterproof system triggered (leak)Miele
• LC / LELeak detectedSamsung
• F8E4Water in the drip trayWhirlpool
• F6E4Water float switch faultWhirlpool

Last reviewed 2026-10-19.