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San Marcos, 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 Part 5
Based on
2021 Uniform Plumbing Code, Chapters 1-17
Water softener rule
No saline discharge into sewer or waterways
Storm water rule
No discharge into City storm drain system
BMP devices
Cannot be abandoned, modified, or removed

Summary

San Marcos plumbing permits run on the 2025 California Plumbing Code, adopted by reference under Municipal Code Section 17.16.010 and based on the 2021 Uniform Plumbing Code. Local amendments in the same chapter ban saline-discharging water softeners and outlaw dumping anything into the City's storm water system.

The 2025 California Plumbing Code, California Code of Regulations, Title 24, Part 5, based on the Uniform Plumbing Code 2021 Edition, Chapters 1 through 17, and Appendices Chapter A, B, D, E, F, G, I and K and the Installation Standards, published by the International Association of Plumbing and Mechanical Officials are adopted by reference subject to amendments contained in this Chapter.

(Ord. No. 2019-1478, Exh. A, § 1.E, 10-22-2019; Ord. No. 2022-1526, § 1.E(Exh. A), 10-25-2022; Ord. No. 2025-1575, § 1.E(Exh. B), 1-13-2026)

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).

Full Breakdown

010 adopts the 2025 California Plumbing Code, California Code of Regulations Title 24 Part 5, based on the 2021 Uniform Plumbing Code, Chapters 1 through 17, plus Appendices A, B, D, E, F, G, I, and K and the Installation Standards published by the International Association of Plumbing and Mechanical Officials, subject to San Marcos's own amendments. 7 to make it unlawful to install or replace any plumbing equipment, including an automatic or self-regenerating water softener unit, whose operation could discharge saline waste into the sewer system or pollute any surface or underground stream, watercourse, lake, or other body of water; this targets self-regenerating softeners that periodically flush concentrated brine.

3, making it unlawful to discharge any material, directly or indirectly, into the City's storm water conveyance system, or to abandon, modify, remove, or destroy a Best Management Practice device installed to control storm water pollutants, unless done consistent with the City's Storm Water Management Program, the permit issued by the Regional Water Quality Control Board, or other federal or state law; any modification to a storm water conveyance system needs City approval first.

Violations & Fines

Installing a saline-discharging water softener or dumping material into the storm drain system violates Sections 17.16.030 and 17.16.040 and is enforced alongside standard Building Code permit violations: the Building Official can require removal of noncompliant equipment, order restoration of any damaged Best Management Practice device, and withhold plumbing permit approval until the installation is corrected, in addition to any separate enforcement the Regional Water Quality Control Board pursues under its own storm water permit.

Frequently Asked Questions

What plumbing code does San Marcos enforce?
The 2025 California Plumbing Code, California Code of Regulations Title 24 Part 5, based on the 2021 Uniform Plumbing Code, applies under Section 17.16.010, along with local amendments on water softeners and storm water discharge in the rest of Chapter 17.16.
Are self-regenerating water softeners legal in San Marcos?
Only if they can't discharge saline waste into the sewer or pollute a stream, watercourse, lake, or other body of water. Section 17.16.030 makes it unlawful to install or replace any water softener unit whose operation could cause that kind of discharge.
Can I connect a sump pump or condensate line to the storm drain?
Not if it discharges anything into the City's storm water conveyance system. Section 17.16.040 makes any such discharge unlawful and also bars removing or disabling Best Management Practice devices installed to keep pollutants out, unless the City's Storm Water Management Program or a state or federal permit specifically allows it.

Sources & Official References

Other rules in San Marcos

All San Marcos rules

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