Why Won't My New Dishwasher Drain?
Recently, a regular customer asked me about dishwasher installation pricing. Since they're a repeat customer, I offered a discounted rate of $50. However, they mentioned they had already installed it themselves but were having drainage issues. I immediately knew what the problem was and provided a quick solution over the phone - free of charge!
The Common Problem
When installing a new dishwasher, the installation process itself isn't complicated - there are plenty of online tutorials available. However, the drainage connection is where most people run into trouble, especially when connecting to a garbage disposal.

Diagram showing the circled area where the knockout plug needs to be removed
The Solution
The issue is that new garbage disposals come with a sealed knockout plug in the dishwasher connection port (the circled area in the diagram). This plug must be removed before connecting your dishwasher's drain hose.
Step-by-Step Fix
1. Turn off the garbage disposal and unplug it for safety
2. Locate the dishwasher connection port on your garbage disposal
3. Use a screwdriver or hammer to carefully remove the knockout plug
4. Connect your dishwasher's drain hose to the now-open port
5. Secure the connection with a hose clamp
Pro Tip
Always check if the knockout plug has been removed before installing a new dishwasher. This simple step can save you hours of troubleshooting!
Need Help?
If you're having issues with your dishwasher installation or any other home improvement projects, feel free to comment below or contact us directly. I'm always happy to help with simple questions!
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