Why did you have an additional assessment for July 1 to June 2018? This assessment should have been paid mostly by the buyer since you sold on July 2017. See below for seller paid taxes.
You can claim any property (real estate) tax you were charged in
your closing costs. Look for a "real estate tax", "property
tax" or “county taxes” charge on settlement statement note delinquent taxes are not deductible but are part of basis.
You should only deduct property taxes for the period that you owned the property, which appears to be 4 or 5 months. If you had to pay delinquent taxes when you bought the house, these are capitalized as part of the cost of the house.
Sale of real estate. The buyer and the seller must divide real estate taxes according to the number of days that each owned the property during the year. Both are considered to have paid their share of taxes, even if one or the other paid the entire amount.
Buyer-paid taxes. Deductible by the buyer only for the period he owned the property. The buyer cannot deduct the real estate taxes of the seller. The buyer must add these taxes to the basis of the property. The seller treats this as additional sales proceeds.
Seller-paid taxes. If the seller pays real estate tax owed by the buyer (beginning on the date of sale), the buyer is considered to have paid the tax. The tax is deductible by the buyer. The buyer must reduce the basis in the property by the tax paid. The seller treats this as a reduced selling price.
