Garbage Disposal Not Working: Common Causes
If you are replacing an identical model and have basic mechanical experience, a direct swap-out using an existing quick-mount ring is manageable. However, if the new disposal requires adjusting the P-trap height, electrical hardwiring, or knocking out the dishwasher drain plug, hiring a licensed plumber ensures watertight connections and prevents water damage to kitchen cabinetry.
The single most common installation mistake on new disposals is forgetting to knock out the dishwasher inlet plug. Inside the disposal’s 3/4-inch side inlet nipple, a factory-molded plastic plug seals the chamber. Before attaching your dishwasher drain hose, you must take a screwdriver and hammer, punch the plug into the disposal chamber, and remove the plastic slug with pliers. If omitted, your dishwasher will fail to drain and flood your kitchen floor.
2. The Disposal Has Zero Power (Tripped Reset Button)
If the disposal makes no sound at all, the internal thermal overload switch has tripped to protect the motor from overheating. Look on the bottom or lower side of the disposal housing under the sink for a small red push button. Firmly press the button until it clicks, and retest.
3. Water Leaking From the Disposal Housing
Inspect where the water is coming from: if it is leaking from the slip-joint drain elbow or dishwasher inlet hose, replacing the gasket or tightening the clamp can fix it. However, if water is weeping from the lower motor casing seam, internal mechanical seals have permanently failed, requiring full disposal replacement.
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