Cal. Water Code § 31142.34

If, after the hearing, the general manager determines that a public nuisance exists, the district shall, by certified mail, send a notice to the record owner requiring that the record owner abate the public nuisance within a specified time. The notice shall state that, unless the public nuisance is abated within the time specified by the district, the district may abate the public nuisance and the costs of the abatement will be assessed against the property.