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Carlsbad, CA Building Safety: Plumbing Permits (2026)

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

Key Facts

Adopted code
2025 California Plumbing Code, Title 24
Appendices kept
H (sewage disposal) and M (water demand)
Roof drainage design
3.7 in/hr, 100-year storm event
Recycled water lines
Need a copper bypass test tee
Enforcement
Runs through Building Code Sections 103-116

Summary

Carlsbad Municipal Code Section 18.16.010 adopts the 2025 California Plumbing Code in full as the city's plumbing code, keeping Appendix H for private sewage disposal and Appendix M for peak water demand while deleting the model code's own administrative sections in favor of the city's building code permit and enforcement rules.

A. The 2025 California Plumbing Code, California Code of Regulations, Title 24, a portion of the California Building Standards Code, is adopted and incorporated by this reference as the plumbing code except for changes, additions, deletions and amendments in this chapter. The following appendices of the plumbing code are included in the adoption: Appendix H (Private Sewage Disposal Systems) and M (Peak Water Demand Calculator). The following sections, chapters, or appendices are deleted: Sections 103, 104, 106, and 107 of Chapter 1; and Appendices A through G, I through L, and N through S.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 5007221; v20 updated 2026-06-16).

Full Breakdown

010(A) adopts the 2025 California Plumbing Code, Title 24 of the California Code of Regulations, with Appendix H (Private Sewage Disposal Systems) and Appendix M (Peak Water Demand Calculator) included, while deleting Sections 103, 104, 106, and 107 of the plumbing code's own Chapter 1 along with most of its appendices. Subsection B applies the adopted code to any plumbing equipment, system, material, or appurtenance installed, used, or designed for use in the city, and subsection C routes permits, fees, stop work orders, violations, penalties, and appeals through the building code's Sections 103, 104, and 108 through 116 rather than the plumbing code's own deleted administrative chapter.

11 to require any new building using recycled water for irrigation to install a copper bypass tee on the building supply pipe, above ground and before the pressure regulator, built to Engineering Standard Drawing W35, with a full-port ball valve on the inlet side and a padlocked, hose-threaded ball valve on the side inlet so the recycled-water cross-connection can be shut down and tested with a backflow prevention device. 7 inches per hour in a one-hour, 100-year storm event, with systems sized by roof area and slope for each drain inlet and calculations submitted with the plan for approval.

Violations & Fines

Because Section 18.16.010(C) routes plumbing enforcement through the building code's administrative chapter, an unpermitted plumbing installation is cited under Section 18.03.020: an infraction for the first three violations in a year, rising to a misdemeanor for the fourth and any later violation, with penalties set by Section 1.08.010 at up to a $1,000 fine, six months in county jail, or both, plus separate-offense treatment for each day the violation continues.

Frequently Asked Questions

What plumbing code does Carlsbad actually enforce?
The 2025 California Plumbing Code, Title 24 of the California Code of Regulations, adopted whole under Section 18.16.010 with Appendix H (Private Sewage Disposal Systems) and Appendix M (Peak Water Demand Calculator) kept, while the model code's own administrative Sections 103, 104, 106 and 107 are deleted and replaced by the city's building code procedures.
How does the city size roof drains for new construction?
Section 18.16.030 requires designers to use a rainfall rate of 3.7 inches per hour in a one-hour, 100-year storm event as the guideline for minimum roof drainage system sizing, based on roof area and slope for each drain inlet, with calculations submitted alongside the plan for approval.
What's required if my new building uses recycled water for irrigation?
Section 18.16.020 requires a copper bypass tee installed above ground on the building supply pipe before the pressure regulator, with a full-port ball valve on the inlet side and a padlocked, hose-threaded ball valve on the side inlet, built to Engineering Standard Drawing W35, so the cross-connection can be shut down and tested with a backflow prevention device.

Sources & Official References

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