(6)     the amount of the lien; and   

(7)     if the lien is for more than one period of time, the date for which the lien is established.   

B.     A lien for charges or assessments which are provided for or fixed by any one ordinance or under authority of law may be included in the same notice of lien, and it shall not be necessary to file separate liens against the separate properties. The lien shall be attested in the name of the municipal clerk under the seal of the municipality.   

C.     The principal amount of any lien imposed for a municipal utility charge or assessment shall bear interest at the rate of twelve percent per year from the date of filing the notice of the lien unless otherwise provided by law.