Garbage disposal runs but the sink fills with water when the dishwasher drains.

Safety first: Turn off power to the disposal and dishwasher before working on hoses.

• Check for air gap or high loop: Ensure the dishwasher drain hose either passes through an air gap fitting or is looped up under the countertop before connecting to the Maxmatic inlet.
• Clean the inlet: Remove the dishwasher hose from the disposal and clear any debris from the inlet port.
• Inspect hose routing: Correct any low spots or sags in the hose that can trap water and promote backflow.
• Verify main drain: If water still backs up, the main kitchen drain may be partially clogged and require snaking.

Proper hose routing and a functioning air gap or high loop are essential to prevent dishwasher water from filling the sink through the disposal.