How to Install a Dishwasher — Plumbing Side

The cabinet side is straightforward; the plumbing details are where most installs fail inspection or leak.

Common causes

• No air gap or high loop on the drain line
• Braided supply line kinked at the shut-off
• Drain line tied in below the disposal inlet
• No dedicated shut-off under the sink

Step-by-step

1. 01Install a dedicated 3/8" quarter-turn stop under the sink
2. 02Run a braided stainless supply line — never plastic
3. 03Loop the drain hose to the underside of the counter (high loop)
4. 04Tie into the disposal or a wye above the P-trap

When to call Northbridge

• No shut-off under the sink for the dishwasher
• Code requires an air gap (some jurisdictions)
• Rough-in isn't in place for a new install
• Old install is leaking and needs redoing