Use the live official source because codes, processes, departments, forms, contacts, fees, and guidance can change.
DOWNTOWN SEATTLE / GUIDE
Downtown Plumbing Source Index
The index covers interior plumbing code, permits, high-rise coordination, water service, private line inspection, side sewers, backups, water quality, and provider verification.
PRACTICAL GUIDE
Use the source that owns the question
Current Seattle, SPU, Public Health, SDCI, and Washington L&I references.
Every link supports only the narrow statement attributed to it.
Read current pages before relying on a rule
Seattle plumbing enforcement, SDCI project review, SPU water and side-sewer processes, and Washington provider verification answer different questions. The register below records the narrow reason each official page was used and the date it was reviewed.
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OFFICIAL SOURCES
SEATTLE AND WASHINGTON ROUTES
Seattle Plumbing Code
OFFICIAL / REVIEWED 2026-09-04Current code edition and Public Health enforcement authority.
2021 Seattle Plumbing Code
OFFICIAL / REVIEWED 2026-09-04Permit requirements, exceptions, and compliance context.
SDCI Permit Process
OFFICIAL / REVIEWED 2026-09-04Applications and pre-submittal coordination, including high-rise and atrium projects.
SDCI Services
OFFICIAL / REVIEWED 2026-09-04Permit, inspection, code, Public Health, utility, and agency routing.
SPU Water Service
OFFICIAL / REVIEWED 2026-09-04Public water service, private line, backflow, and project process.
SPU Private Water Line Inspections
OFFICIAL / REVIEWED 2026-09-04Exterior private water piping inspection before covering.
SPU Your Side Sewer
OFFICIAL / REVIEWED 2026-09-04Private and shared side-sewer ownership and support.
SPU Side Sewer Permits
OFFICIAL / REVIEWED 2026-09-04Side-sewer scope, property and right-of-way work, and related records.
SPU Side Sewer Application
OFFICIAL / REVIEWED 2026-09-04SPU permit issuance through the Seattle Services Portal since October 1, 2025.
SPU Sewer Backup Guidance
OFFICIAL / REVIEWED 2026-09-04Exposure control, private assessment, public investigation route, and event documentation.
SPU Sewer System
OFFICIAL / REVIEWED 2026-09-04Private side sewers, SPU assets, and King County system context.
SPU Water Quality Reports
OFFICIAL / REVIEWED 2026-09-04Current and historical system water-quality reporting.
Washington L&I Verify
OFFICIAL / REVIEWED 2026-09-04Contractor registration, tradesperson certification, and related public records.
Washington L&I Protect My Home
OFFICIAL / REVIEWED 2026-09-04Planning, written bids, verification, and written agreement guidance.