Are used car dealers in Washington State required to disclose the fact a vehicle was a prior rental car before you buy it?

Most used car dealers in the United States must comply with federal disclosure laws. Check the FTC's website for detailed disclosure requirements here: http://business.ftc.gov/documents/bus13-dealers-guide-used-car-rule. The Washington State Attorney General does a really nice job summarizing used car disclosure requirements under Washington law at http://www.atg.wa.gov/ConsumerIssues/Cars/UsedCars.aspx#Research_vehicle. In general, if the vehicle was sold "As Is," a legal term of art explained at the AG's website, the answer is probably "no." Check these guides, and then read your paperwork carefully. If you are still unsure, schedule a consultation with an attorney here in the Tri-Cities, and make sure you take all paperwork to the consultation. Good luck!