The state of Washington is telling its retailers that B.C. residents don't qualify for an exemption on paying Washington's sales tax.

The state's revenue department has issued a statement saying some B.C. residents appear to believe they're exempt from the tax and have been making such claims with retailers.

But the department says the exemption only applies to people from jurisdictions with a sales tax of three per cent or less, such as Alberta and Oregon, and not to places with a seven per cent sales tax, like B.C., whether it's under the harmonized tax or PST.

The department is warning Washington retailers they may be liable for any uncollected sales tax if they give exemptions to B.C. residents.