Unsecured Property Tax payment deadline. Partial payments are not acceptable.The first step to get help with paying your fees and tuition is to submit an application for financial assistance. Payments on a collections account can be made at any Contra Costa County Superior Court location Monday-Friday, am to pm (except holidays). Taxpayers in most of California now have until November 16, 2023, to file various federal and state individual and business tax returns and make tax payments.