Washington (WA) Plumbing Code & Permit Rules
Uniform Plumbing Code (2021)
Data: State plumbing boards, ICC, IAPMO, EPA
Our reference data lists several plumbing requirements for Washington; confirm details with your local building department. Our regulation records list a licensed plumber for most work, annual backflow testing, and seismic strapping for water heaters; requirements vary by location and installation. Homeowners should budget for professional plumbing services and compliance costs.
Plumbing Code
Washington follows the Uniform Plumbing Code (2021 edition).
Key Regulations
| Regulation | Status | Details |
|---|---|---|
| Plumbing Code | UPC (2021) | Uniform Plumbing Code |
| Homeowner DIY | Not allowed | Check the applicable state and local licensing rule for the planned plumbing work |
| Water Heater Permit | Required | Seismic strapping required in seismic hazard zones; licensed plumber required |
| Backflow Testing | Annual, required | |
| Seismic Strapping | Required | Water heater restraint |
DIY Plumbing in Washington
Washington requires a licensed plumber for most plumbing work. Check the applicable state and local licensing rule for the planned plumbing work
While this increases costs, it ensures:
- Work meets current code requirements
- Proper permitting and inspection
- Warranty and liability protection
- Safe connections to water and sewer systems
Backflow Prevention
Washington requires annual backflow testing to protect the public water supply from contamination. Testing must be performed by a Certified tester.
Non-compliance penalty: Water service may be shut off if testing is not completed on schedule.
Water Conservation Requirements
Washington has state-specific water conservation mandates. State water conservation standards tied to building codes
Lead Service Line Replacement
Washington is subject to EPA lead service line inventory and replacement requirements.
Data Sources
- Washington state plumbing board and licensing agency
- International Code Council (ICC)
- IAPMO
- EPA Safe Drinking Water Act
Updated as regulations change.
Need a licensed plumber in Washington?
Plumbing regulations vary by city. Connect with a licensed professional who knows your local code requirements.
Find a Licensed Plumber →Frequently Asked Questions
What plumbing code does Washington follow?
Washington follows the Uniform Plumbing Code (2021 edition) as of our last review; state and local amendments may apply.
Can I do my own plumbing work in Washington?
Our reference data lists Washington as requiring a licensed plumber for most plumbing work; homeowner exemptions may apply, so check state and local permit rules.
Do I need a permit to replace a water heater in Washington?
Permit rules for water heater replacement in Washington depend on the state and your local jurisdiction; check with your local building department. Check whether state and local rules require a licensed plumber for the installation.
Is backflow testing required in Washington?
Backflow testing requirements in Washington depend on the state code and your water utility; check with your utility about which assemblies must be tested and how often.
Does Washington require seismic strapping for water heaters?
Our reference data lists a seismic strapping requirement for water heaters in Washington; confirm it with your local building department. This typically involves two metal straps securing the water heater to the wall to prevent toppling during an earthquake.