Three things that need to be installed new
1
Hot water supply
Plumber adds T-fitting on hot pipe, shutoff valve, runs 3/8" line. Straightforward if under-sink hookup is nearby.
$100-300DIY-feasible
2
Drain line
Tap into sink drain or disposal. High loop or air gap (CA code requires air gap). Backflow prevention non-negotiable.
$75-200DIY-feasible
3
Electrical circuit
Dedicated 120V 20-amp. Why dedicated matters: shared circuits trip under load. Permit + electrician required.
$250-900Permit
Connection schematic · FIG. 13 points
Where in the kitchen? Location drives cost
| Location | Complexity | Labor Total |
|---|---|---|
| Adjacent to existing sink | Lowest | $300-500 |
| Same wall, longer run | Moderate | $400-700 |
| Kitchen island | Moderate-high | $500-800 |
| Far wall (wall opening) | Highest | $700-1,500 |
Step-by-step: what the plumber does
- 01Assess existing under-sink plumbing & space
- 02Install hot water T-fitting & shutoff valve
- 03Run 3/8" supply line to dishwasher location
- 04Tap drain into sink drain or garbage disposal
- 05Route drain hose with high loop or air gap
- 06Coordinate with electrician for 20-amp circuit
- 07Connect dishwasher inlet & drain at install
- 08Pressure-test and run leak check
Permits for first-time installations
New plumbing + new electrical = permits almost always required.
Skipping permits creates problems at resale (failed home inspection), can void homeowner insurance for related damage, and risks code violation notices. California enforces particularly strictly. See the full permit guide for state-by-state detail.
Finding the right contractor
- Licensed plumber for water and drain lines
- Licensed electrician for the new dedicated circuit
- General contractor if walls need opening or full renovation context
- Get separate quotes for plumbing and electrical so you can compare