Martin receives the following tax bills, related to a rental dwelling, from the county treasurer:

Special assessment for installing sidewalks and streets .....$ 12,000

Real property tax on dwelling for the 1/1/20–12/31/20

property tax year, due on 10/1/20 ..........................................$ 1,500

On May 1, 2020, Martin sells the dwelling for $70,000. His basis in the dwelling at the date of sale is $40,000. Martin’s basis in the dwelling does not reflect the property tax bills. As part of the sale contract, the buyer agrees to pay the real property taxes when they come due on October 1, 2020, but Martin has to pay the special assessment before the sale closes. What is the proper tax treatment of the tax payments?