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Washington · Property taxWashington property tax: the April and October due dates, interest, the lien and the statutory split

Washington real property taxes are due to the county treasurer on or before April 30 and are delinquent after that date; when the tax on a tract is $50 or more and half is paid by April 30, the rest is due by October 31. Payments mailed with no discernible postmark and received within three business days of either date aren't delinquent. Delinquent taxes bear interest computed monthly from delinquency: since January 1, 2023, 9% a year for residential property of four or fewer units, including manufactured homes, and 12% for other property; penalties of 3% on June 1 and another 8% on December 1 apply to other property but may not be assessed on residential property of four or fewer units (RCW 84.56.020). The tax is a lien on the real property from January 1 of the year it is levied until paid, and when the seller and buyer haven't agreed who pays the taxes due in the year of the sale, the seller owes the share for the part of the year before the sale and the buyer the rest (RCW 84.60.020).

What the statutes set

  1. Due dates (RCW 84.56.020(1), (3))

    April 30; with half paid by then, the rest by October 31.

  2. Interest (RCW 84.56.020(5)(a))

    9% a year on 1–4 unit homes, 12% on other property, monthly from delinquency.

  3. Penalties (RCW 84.56.020(5)(b))

    3% June 1 and 8% December 1 – not on 1–4 unit homes.

  4. Lien and split (RCW 84.60.020)

    Lien from January 1; if the contract is silent, prorated by the sale date.

What the TC does with Washington property tax at closing

  • Check whether the first half (April 30) or second half (October 31) is paid before closing.
  • Confirm the purchase agreement says who pays the year's tax – otherwise the statutory split applies.
  • Get the treasurer's payoff, with interest, for any delinquent half.

Questions about Washington property tax

When is Washington property tax due?

By April 30; when the tax is $50 or more and half is paid by April 30, the second half is due by October 31 (RCW 84.56.020).

Who pays Washington property tax in the year of a sale?

Whoever the contract says; if it says nothing, the seller pays the share for the part of the year before the sale and the buyer the rest (RCW 84.60.020).

Related guides

Put the April 30 and October 31 dates and the tax payoff on the deal's closing tasks in ClosingCode.

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Sources: RCW 84.56.020, 84.60.020 (app.leg.wa.gov), read October 30, 2026.

General information, not legal or tax advice. ClosingCode is software; it is not a law firm or brokerage. This guide is not a substitute for the advice or services of an attorney.