The grantor reports the real estate sale and claims the withholding on their tax return. Complete Form 593 using the grantor's information.Purchasers of property at the tax sale must also pay a Documentary Transfer Tax on the amount of the bid. When Are Property Taxes Due in Contra Costa County? The percentage of withholding may differ for entities. County transfer tax is computed on the full value of the property. Download PDF BOE-266 REV. August saw 895 property sales, which was down from a total of 1,138 a year ago. Your mortgage interest statement provides documentation if this is the case or not. What are the California Property Tax Rates?