In California, your ESA housing rights rest first on state law. California AB 468 (Health & Safety Code § 122318) sets the requirements for a valid ESA letter, including a 30-day client-provider relationship. This state protection is enforced by California Civil Rights Department and remains fully active. The federal Fair Housing Act (42 U.S.C. § 3604) provides the same obligation, and that statute has not changed.
Landlords in Chico who refuse a valid ESA letter or continue charging pet fees may be in violation of AB 468 and federal law. Complaints can be filed with California Civil Rights Department.