Antioch, CA Rental Property Rules: Mold Disclosure (2026)

California's Toxic Mold Protection Act of 2001 (Health & Safety Code §§26100–26156) authorizes the California Department of Public Health to set permissible mold exposure limits; until those limits are adopted, landlords must disclose the presence of known visible mold that exceeds common health guidelines or that could affect tenant health. Disclosure must be in writing before lease signing and to all current tenants when mold is discovered. Independent of the Mold Act, Civil Code §1941.1(a)(10) makes a dwelling untenantable when it is "infested with... mold... that endangers the life, limb, health, property, safety, or welfare" of occupants, giving tenants statutory remedies (repair-and-deduct under §1942, withholding rent, or suing for damages). Antioch Municipal Code Chapter 6-4 (Property Maintenance) and the adopted California Housing Code authorize Code Enforcement to declare a unit substandard where dampness, leaks, or mold create a health hazard. Inspectors typically require the underlying water source to be corrected (plumbing leak, roof leak, inadequate ventilation) and visible mold remediated using industry practices (IICRC S520). Remediation of contaminated areas >10 sq ft generally requires a licensed mold remediation contractor under Business & Professions Code §7031. Tenants may report unresolved mold to Contra Costa Environmental Health or pursue civil action. Landlords who fail to disclose or remediate face habitability claims, rent abatement, and potential relocation assistance liability.