Except as provided in subsection (b) of this section, interest is calculated on and charged against the total tax liability on property. When payments of property tax have been made, interest is calculated on and charged against the total tax liability on the property, less the amount of the payments.

The rate of interest for State property tax is 1% for each month or fraction of a month that State property tax is overdue.

Except as provided in subsection (b) of this section and for estimated personal property tax in § 14-604 of this subtitle, the rate of interest for full year county or municipal corporation property tax or taxing district property tax is two-thirds of 1% for each month or fraction of a month that the county or municipal corporation property tax or taxing district property tax is overdue. For the following counties and municipal corporations the rate of interest for each month or fraction of a month that county or municipal corporation property tax or taxing district property tax is overdue is: 5% for Garrett County; 1% for the City of Salisbury; 1% for Washington County; 1% for Somerset County; and the rate set by law by: the governing body of a county that has adopted a charter form of government under Article XI–A of the Maryland Constitution; the governing body of: Allegany County; the City of Annapolis; Berlin, not exceeding 1.5%; Caroline County, not exceeding 1%; Cecil County, or any municipal corporation in Cecil County, not exceeding 1%; Dorchester County; the City of Frederick, not exceeding 1%, that is set on or before the date of finality; Frederick County, not exceeding 1%, that is set on or before the date of finality; Ocean City, not exceeding 1.5%; Pocomoke City, not exceeding 1.5%; the Town of Princess Anne, not exceeding 1.5%; Kent County or any municipal corporation in Kent County; Queen Anne’s County or any municipal corporation in Queen Anne’s County; Snow Hill, not exceeding 1.5%; Worcester County, not exceeding 1.5%; Calvert County; St. Mary’s County; the City of Taneytown; the City of Cambridge; or Mardela Springs, not exceeding 1%; or the Mayor and City Council of Baltimore City for Baltimore City, if the rate is set on or before June 30 for the following taxable year. The governing body of Calvert County or of St. Mary’s County may set, by law: an interest rate for overdue tax on commercial property; and a separate interest rate for overdue tax on noncommercial property.

The Mayor and City Council of Baltimore City or the governing body of a county or of a municipal corporation may set, by law, an interest charge for: overdue final determination of estimated county or municipal corporation property tax on personal property or operating property; or overdue 1/4, 1/2, or 3/4 year county or municipal corporation property tax or taxing district property tax on real property.

If a person fails to pay property tax when required by this article, the person shall pay interest on the total tax liability on property for each month or fraction of the month from the date the property tax payment is required to be paid under Title 10 of this article to the date the tax is paid.

If a person is granted a deferral that extends the time to pay Montgomery County property tax or Prince George’s County property tax under § 10-201 of this article, the person shall pay interest on the county property tax payment from the due date without a deferral until the date that the county property tax is paid.

The governing body of a county may provide, by law, for interest on advance payments of county property tax. The interest allowable under subsection (a) of this section may not exceed the discount for the taxable year that the county allows for the county property tax on the property.

The governing body of a county or of a municipal corporation shall provide, by law, for the payment of interest on refunds of county or municipal corporation estimated property tax on personal property or operating property.

Subject to § 14-919 of this title, on the final determination of an appeal under Subtitle 5 of this title, any money paid by a taxpayer that exceeds the amount properly chargeable under the determination shall be refunded at the same rate of interest that the taxes would have borne if the taxes were determined to have been overdue.