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Benton County, WA Building Safety: Plumbing Permits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Governing section
BCC 3.08.010
Code adopted
2021 Uniform Plumbing Code (with Appendices A, B, I)
Excluded chapters
UPC Chapters 12 and 14, plus venting/sewer portions
Contractor requirement
Certificate of competency under RCW 18.106
Administering agency
Benton County Building Department, BCC 3.08.070

Summary

Benton County adopts the 2021 Edition of the Uniform Plumbing Code under BCC 3.08.010, requiring every plumbing installation, alteration or repair in unincorporated territory to conform to that code, with limited local exceptions for venting, combustion air and building sewers.

City-specific rules exist: Kennewick has its own plumbing permits rules that differ from Benton County's county-level regulations. If you live in Kennewick, check the city-specific page instead.

3.08.010 ADOPTION OF UNIFORM PLUMBING CODE AND UNIFORM PLUMBING CODE STANDARDS. The 2021 Edition of the Uniform Plumbing Code, including appendices A, B and I and Uniform Plumbing Code Standards published by the International Association of Plumbing and Mechanical Officials, except Chapters 12 and 14 thereof and those requirements of the Uniform Plumbing Code relating to venting and combustion air of fuel fired appliances as found in chapter 5 and those portions of the code addressing building sewers, as now adopted or hereafter amended by the State of Washington, is hereby adopted by Benton County and all plumbing hereafter installed, altered, repaired, added to, used or maintained shall be done in conformity with the provisions of the Uniform Plumbing Code and Uniform Plumbing Code Standards, except as expressly provided herein.

Full Breakdown

010, most recently amended by Ord. 651 (2024), adopts the 2021 Edition of the Uniform Plumbing Code and its Appendices A, B and I, plus the Uniform Plumbing Code Standards published by the International Association of Plumbing and Mechanical Officials, as amended by the State of Washington. The county excludes Chapters 12 and 14 of that code, along with the venting-and-combustion-air provisions in Chapter 5 and the portions addressing building sewers, from local adoption. Every plumbing system 'hereafter installed, altered, repaired, added to, used or maintained' in unincorporated Benton County must conform to the adopted code.

106 RCW, and the Benton County Building Department will not issue a required plumbing permit until the applicant supplies proof of that certification and registration. 025. 070, appointing the inspector or inspectors responsible for all inspections the Uniform Plumbing Code requires.

Violations & Fines

Beginning plumbing work without the required certificate of competency and registration, or without a permit where one is required, violates BCC 3.08.080. The Building Department can withhold permit issuance entirely until certification proof is supplied, and general enforcement of BCC Title 3 building provisions includes civil penalties and injunctive relief for continued noncompliance.

Frequently Asked Questions

What plumbing code does Benton County use?
BCC 3.08.010 adopts the 2021 Edition of the Uniform Plumbing Code and its Uniform Plumbing Code Standards, as amended by Washington State, excluding Chapters 12 and 14 and the venting/combustion-air and building-sewer portions of Chapter 5.
Do I need a certification to do plumbing work in unincorporated Benton County?
Yes. BCC 3.08.080 requires a valid certificate of competency under Chapter 18.106 RCW before anyone may install, remove, alter, relocate, replace or repair plumbing or drainage systems, and the Building Department withholds permits until that proof is supplied.
Who inspects plumbing work in Benton County?
The Benton County Building Department administers Chapter 3.08 under BCC 3.08.070 and appoints the inspector or inspectors responsible for all inspections required by the adopted Uniform Plumbing Code and its standards.

Sources & Official References

Other rules in Benton County

All Benton County rules

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