Iowa Code § 468.589: Rates and charges for services and connection.

If a county and city have entered into an agreement pursuant to chapter 28E to create an urban drainage district, the county or city or both may, to the extent and in the manner provided in the agreement, establish, impose, adjust, and provide for the collection of rates to produce gross revenues at least sufficient to pay the expenses of operation and maintenance of a drainage improvement against property within the district and establish, impose, adjust, and provide for the collection of charges for connection to a drainage improvement. Rates and charges must be established by ordinance of the governing body of the county or city imposing the rates or charges. Rates or charges for the services of and connection to the drainage improvement if not paid as provided by the ordinance of the governing body, are a lien upon the premises served or benefited by that improvement and may be certified to the county treasurer and collected in the same manner as other taxes.