California Law
California was one of the first states to legislate around indoor mold. The rules are more about disclosure and habitability than mandatory testing — here's the plain-language version.
This is general information, not legal advice. Tenant-landlord and real estate disputes are fact-specific. If you're in an active dispute, consult a California tenant-rights attorney or your local legal aid office.
California's habitability standard (rooted in Civil Code §1941.1 and related health & safety code provisions) requires rental units to be fit to live in. Visible, significant mold tied to a structural moisture problem — a leaking roof, failed plumbing, or water intrusion the landlord hasn't fixed — can qualify as a habitability issue.
California's Health & Safety Code (Section 26140 area) established mold guidelines, and more practically, sellers have a general legal duty to disclose known material facts about a property — known mold problems typically qualify. This usually shows up in the Transfer Disclosure Statement (TDS) required in most residential sales.
For multi-unit buildings, mold in one unit is often a symptom of a building-wide moisture issue (roof, common-area plumbing, ventilation design). Property managers and HOA boards have their own disclosure and maintenance obligations under California's Davis-Stirling Act and related housing law — a pattern of mold complaints across multiple units is worth raising as a building issue, not just a unit-by-unit one.
Have a specific mold situation and not sure what applies? See the FAQ, or start with independent testing to get a documented starting point before any legal conversation.