Water Code § 51515
ARTICLE 2. Original and Additional Assessments
Assessments unpaid after 30 days and accrued interest thereon shall be collected by and paid to the county treasurer of the county wherein the parcel is situated, or the board may designate an agent to effect such collection who shall file with the treasurer of such county a detailed report of any and all collections thereon and who shall deposit the money with that county treasurer to the credit of the district.