Redwood City, CA Building Safety: Plumbing Permits (2026)
Key Facts
- Adopted plumbing code
- 2025 California Plumbing Code (Title 24, Pt. 5)
- Local amendments
- Secs. 9.77-9.82, Bay Mud piping ban
- Banned material
- Metallic water/drain/vent/storm/gas piping underground
- No-permit penalty
- 2x permit fee under Sec. 9.43
- Conflict rule
- Most restrictive adopted code applies
Summary
Redwood City enforces the 2025 California Plumbing Code by reference under Sec. 9.40, plus six local amendments in Sections 9.77 through 9.82 that ban metallic water, drainage, vent, storm and gas piping underground anywhere the city's "Special Bay Mud" map applies.
Title 24, Parts 1, 2, 2.5, 3, 4, 5, 6, 7, 8, 10, 11, and 12 of the California Codes of Regulations, namely the (2025) California Building Codes ..., Residential, Electrical, Mechanical, Plumbing, Energy, Wildland-Urban Interface, Historical Building, Existing Building, Green Building Standards, and California Reference Standards Codes ... are hereby adopted by reference, with the amendments, additions and modifications set forth hereinafter in this Chapter. ... In the event there are conflicts between the provisions of these Codes and other codes or provisions adopted by the City, the most restrictive provision shall apply. ... 604.14 Metallic water piping shall not be used underground in those areas indicated on the map entitled "Where Special Bay Mud Requirements Apply," available through the City website.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Zoning Code: Supplement 29 | City Code: Supplement 61 Update 1).
Full Breakdown
40 adopts Title 24, Part 5 of the California Code of Regulations, the 2025 California Plumbing Code, by reference as the plumbing law of the City, together with the Building, Residential, Electrical, Mechanical and Energy Codes from the same cycle, and states that wherever these adopted codes conflict, the most restrictive provision applies. Article VI of Chapter 9 then layers on six Redwood City-specific amendments addressing the Bay's soft, corrosive Bay Mud soils. 1. A permit applicant working in a mapped Bay Mud area must specify non-metallic materials for each of these systems before the Building Division will approve plans. 7B of the Redwood City Code, with each day of a continuing violation a separate offense.
Violations & Fines
Installing or maintaining plumbing work that violates the adopted 2025 Plumbing Code or any of the Bay Mud metallic-piping amendments is unlawful under Section 9.3, punishable under Section 1.7B of the Redwood City Code, with the Building Official or an authorized Building Division representative empowered to issue citations. Each day the violation continues counts as a separate offense, and working without the required permit adds a fine equal to twice the permit fee under Section 9.43.
Frequently Asked Questions
What plumbing code does Redwood City use?
Why can't I use metal pipe underground in parts of Redwood City?
What happens if I install plumbing without a permit?
Sources & Official References
Other rules in Redwood City
California rules heatmap·Compare Redwood City to another location·View the California building safety overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.