Short definition
The finish, rough-in, and underground inspections are the three standard stages of plumbing inspection on a permitted project. For the full breakdown — what each stage covers, the WA-specific permit fees, and the contractor-conversation rules that protect you — see the canonical entry: Rough-in inspection stages.
What it is
The three stages, in order:
- Underground. Before slab pour or backfill. Verifies buried drain layout, slope, materials, joints, pressure test.
- Rough-in. Before drywall. Verifies in-wall pipework, supports, nail plates, fire blocks, pressure test.
- Finish (final). After fixtures are installed. Verifies functional fixtures, water-heater straps, drain operation, pressure-test.
WAC 51-56 (WA-amended UPC) Chapter 3 governs inspection and testing. Inspections happen in sequence; a failed stage must be corrected before the next is scheduled.
For full coverage including the homeowner-protection rules — never let a contractor close walls before rough-in inspection passes — see rough-in inspection stages.
Why it matters to a homeowner
The crucial rule: drywall goes up only after rough-in inspection passes. A homeowner whose contractor drywalls early may have to cut and redo. Sub-slab drain work for a basement bathroom must pass underground inspection before pouring concrete. A sewage ejector or sump pump install gets reviewed at underground (vault placement) and finish (pump and discharge function).