The state Supreme Court has ruled that a U.S. Postal Service certificate of mailing is not the only document that can establish “proof of mailing” under the notice provision of the Real Estate Tax Sale Law.

In Horton v. Washington County Tax Claim Bureau, a six-justice court ruled 5-1 to reverse a Commonwealth Court decision that because the Washington County Tax Claim Bureau did not obtain a certificate of mailing, it failed to show proof under Section 602 of the Tax Law that it mailed notices of an upset tax sale of a property to the property owners.