(1) As an alternative or in addition to other methods of ascertaining assessments for local improvements, the legislative authority of a municipality may develop and apply a system of classification of properties based upon some or all of the public land use restrictions or private land use restrictions to which such property may be put at the time the assessment roll is confirmed.
(2) The legislative authority of a municipality may classify property into office, retail, residential, public, or any other classifications the legislative authority finds reasonable, and may levy special assessments upon different classes of property at different rates, but in no case may a special assessment exceed the special benefit to a particular property. A municipality also may exempt certain classes of property from assessment if the legislative authority of the municipality determines that properties within such classes will not specially benefit from the improvement.
(3) For each property within a classification, the legislative authority of the municipality may determine the special assessment after consideration of any or all of the following:
(a) Square footage of the property;
(b) Permissible floor area;
(c) Distance from or proximity of access to the local improvement;
(d) Private land use restrictions and public land use restrictions;
(e) Existing facilities on the property at the time the assessment roll is confirmed; and
(f) Any other factor the legislative authority finds to be a reasonable measure of the special benefits to the properties being assessed.
(4) If after the assessment roll is confirmed, the legislative authority of a municipality finds that the lawful uses of any assessed property have changed and that the property no longer falls within its original classification, the legislative authority may, in its discretion, reclassify and reassess such property whether or not the bonds issued to pay any part of such costs remain outstanding. If such reassessment reduces the total outstanding assessments within the local improvement district, the legislative authority shall either reassess all other properties upward in an aggregate amount equal to such reduction, or shall pledge additional money, including money in a reserve fund, to the payment of principal of and interest on such bonds in an amount equal to such reduction.
(5) When the legislative authority of a municipality determines that it will use the alternative or additional method of assessment authorized by this section, it may select and describe the method or methods of assessment in the ordinance ordering a local improvement and creating a local improvement district if such method or methods of assessment have been described in the notice of hearing required under RCW 35.43.150
. If the method or methods of assessment are so selected and described in the ordinance ordering a local improvement and creating a local improvement district, the action and decision of the legislative authority as to such method or methods of assessment shall be final and conclusive, and no lawsuit whatsoever may be maintained challenging such method or methods of assessment unless that lawsuit is served and filed no later than thirty days after the date of passage of the ordinance ordering the improvement, and creating the district or, when applicable, no later than thirty days after the expiration of the thirty-day protest period provided in RCW 35.43.180