Short definition
Rough-in inspection stages are the three (sometimes four) standard inspection points during a permitted plumbing project. Inspectors visit at “open” stages — before slab pour, before drywall, after fixtures — to verify pipe layout, materials, slope, supports, and pressure tests before the work is concealed.
What it is
The three standard stages on a residential plumbing project:
1. Underground inspection
- When. After underground drains are installed and pressure-tested, BEFORE the slab pour or backfill.
- What. Drain layout, slope, materials, joints, hangers, pressure test (water or air).
- Critical. If you backfill or pour first, you have to dig up to fix anything.
2. Rough-in inspection
- When. After all in-wall plumbing is complete and pressure-tested, BEFORE drywall.
- What. Supply lines, drain lines, vents, gas lines, supports, nail plates, fire blocks, water-hammer arrestors, hose bibs, wall-mounted backer blocks.
- Critical. Drywall before this is a major redo.
3. Final / finish inspection
- When. After fixtures are installed and project is complete (after second-fix).
- What. Fixtures functional, traps filled, vents working, water-heater earthquake straps (WA L&I requirement), pressure test, gas-leak test, faucet operation, drain operation.
- Critical. The Certificate of Occupancy or permit final-card depends on this passing.
A gas-only inspection sometimes happens separately for gas piping pressure-test, often combined with rough-in if scheduling allows.
Hydrostatic rough-in pressure test: water-supply piping at 100 psi minimum or 1.5x working pressure for at least 15 minutes (some jurisdictions require 1 hour). Air pressure test on DWV: 5 psi for 15 minutes; or water-fill test (10-foot head) for 15 minutes.
Why it matters to a homeowner
This entry is the homeowner’s most important contractor-protection tool. Five scam-prevention angles to know:
“We don’t need rough-in inspection, this is just a quick remodel”
Verify with the AHJ. For most WA jurisdictions, even a 1-bath remodel requires a plumbing permit if any drain or vent location changes. Like-for-like fixture swap (same toilet, same location): often no permit. New fixture or moved fixture: permit required. Use L&I’s online Verify portal to check the contractor’s license, plus your AHJ’s permit portal to look up the permit by address.
“We’ll get the rough-in inspection after the drywall goes up”
This is the single biggest red flag in a residential plumbing job. Rough-in inspection is BEFORE drywall. Period. A contractor who wants to drywall first is either ignorant of the process or actively trying to hide non-compliant work. The whole point of inspecting at rough-in is to verify nail plates, framing protection, and slope before they’re hidden behind sheetrock.
“The inspector said it passed but didn’t sign anything”
Verify with the AHJ permit portal. Inspections are logged in the city or county permit system. If it’s not in the portal, it didn’t happen.
“Our inspector is buddy-buddy with us”
Inspectors are AHJ employees, not contractor employees. A contractor claiming a “special relationship” with the inspector is hinting at corruption. Report to the AHJ if work is signed off without the inspector visiting.
“Inspection failed, we’ll fix it but don’t worry about it”
Failed inspections are documented. The contractor must correct and re-inspect (at the contractor’s cost in most cases). Verify on the permit portal that the failed item was corrected and re-inspected.
When you’ll encounter this term
- A plumbing permit application listing “underground / rough-in / final” inspection stages.
- A contractor’s quote referencing rough-in and final inspections separately.
- A pre-purchase inspection finding undocumented work.
- A homeowner-pulled permit (RCW 18.106.150 exemption) where the homeowner is responsible for calling inspections.
Common variants and not the same as
- Underground vs. slab inspection. Same idea — inspecting below-grade or under-slab pipework before pour or backfill.
- Rough-in vs. top-out. Some jurisdictions use “top-out” for the same stage when the vertical pipe is complete to the top of the stack.
- Finish vs. final. Synonyms.
- Permit close-out. The final inspection passing closes the permit. An open permit at sale time is a title concern.
Washington note
Seattle SDCI
Plumbing permit fee: $132 base plus $26 per fixture (2025 schedule). King County Public Health collects plumbing fees under section 22.900G.030 — separate from SDCI building permits. Like-for-like replacement in same location is no-permit; any layout change is permit-required.
Tacoma, Bellevue, Olympia, Everett, Spokane
Each AHJ runs its own permit and inspection program. Tacoma Permits at tacomapermits.org or 253-591-5030. Bellevue Development Services. Olympia, Everett, and Spokane each handle through their building departments. Each AHJ may have slightly different fees and inspection scheduling rules.
Re-inspection fees
Failed inspection: $50–$150 typical re-inspection fee (varies by AHJ).
Permit cost ranges
- Single-fixture replacement requiring permit (Seattle): $158
- 5-fixture bathroom remodel (Seattle): roughly $262
- Plumbing-portion of a typical bathroom remodel permit: $200–$600
WAC 51-56 (WA-amended UPC)
Chapter 3 covers inspection and testing, including the hydrostatic test requirement.