Cal. Water Code § 25809

A district may make an additional reasonable charge for processing or reprocessing an invalid check or other instrument used to pay an assessment or service charge owed to the district. The reasonable charge shall be for cost of the processing or reprocessing of the invalid check or instrument. If the charge for processing becomes delinquent, the charge may become a lien against the land on which the assessment was made or to which the service was rendered, as provided in Section 25806.