In Baltimore City, the Mayor and City Council may not sell a property to enforce a lien for unpaid charges for water and sewer service unless: the lien is for at least $350; the property is not: a residential property; or real property that is exempt from taxation under § 7–204(1) or (2) of this article; and the unpaid charges for water and sewer service are at least 3 quarters in arrears. Notwithstanding subsection (a) of this section, the Mayor and City Council may enforce a lien on a property other than residential property or real property that is exempt from taxation under § 7–204(1) or (2) of this article for unpaid water and sewer service that is less than $350 if the property is being sold to enforce another lien. This section does not affect any other right or remedy of Baltimore City for the collection of a water and sewer service charge.