Washington Window Tint Laws: VLT Limits, Exemptions, and Penalties

Washington window tint laws require at least 24% visible light transmission (VLT) on every window of a passenger car except the windshield, and that 24% is measured as the combined light transmission of the factory glass and any film applied on top. Film reflectance cannot exceed 35%, only a single sheet of film may be applied to any given window, and certain colors and finishes are banned outright. Violations are traffic infractions enforced on the roadside with a photometer.

The 24% Rule and How It’s Measured

VLT is the percentage of visible light that makes it through your window. Washington uses a net measurement, which means the state looks at the factory glass and the aftermarket film as a single unit. Most factory glass already blocks some light on its own, so installing a film rated at exactly 24% on typical factory glass will put the combined reading below the legal threshold. This stacking effect is the most common mistake people make when choosing film.

For standard passenger cars, every window other than the windshield must hit the 24% net VLT minimum, and the film’s reflectance must stay at or below 35%.¹

You can only install one sheet of film on any window. Layering two films to combine their properties is explicitly prohibited by statute, even if the combined result would otherwise meet the 24% minimum.¹

Windshield Rules

Standard tint film is off-limits on the windshield itself. What Washington allows is a transparent tint strip along the top edge: no more than six inches down from the top, and nothing extending into the AS-1 portion of the glass that the manufacturer marks as critical for driving visibility. You can also apply clear UV-blocking film across the entire windshield, as long as it doesn’t reduce visible light transmission at all.¹

Federal rules sit on top of state law. Under FMVSS 205, glazing areas needed for driving visibility in passenger vehicles must maintain at least 70% light transmittance. That floor applies to windshields and front side windows regardless of what Washington’s rules otherwise allow.²

SUVs, Trucks, and Vans

Vehicles the manufacturer classifies as trucks, motor homes, or multipurpose passenger vehicles (a category that covers most SUVs, crossovers, and vans) follow a split standard. The front side windows next to the driver and front passenger must still meet the 24% net VLT minimum and 35% reflectance maximum that applies to any sedan.¹

Behind the driver, the rules relax. The rear side windows and back window on these vehicles can go darker than 24% VLT, with no specific minimum, as long as film reflectance stays at or below 35% and the vehicle has exterior mirrors on both sides. The same back-window exemption extends to hearses, limousines, collector vehicles, and ambulances.¹

Classification is what the manufacturer put on your vehicle’s federal certification label, not what the vehicle looks like or how you use it. A two-door SUV qualifies for the rear-window exemption if the manufacturer designated it a multipurpose passenger vehicle. A four-door sedan does not, even with a large cargo area.

Banned Films and Colors

Several categories of film are prohibited outright, regardless of VLT or reflectance numbers:

Mirror-finish products. Any film that creates a reflective, mirror-like appearance is illegal. This goes beyond the 35% reflectance cap and bans the aesthetic itself.
Red, gold, yellow, or black film. Red, gold, and yellow are banned because they can be confused with emergency vehicle lighting. Black is banned by the statute as well.
Spray-on or brush-on tint. Liquid film applied wet is not permitted. Only pre-formed adhesive film sheets are legal.

The black-film rule catches people off guard. “Black” here means the color of the film, not how dark it looks. Most automotive tint sold as charcoal or neutral is designed to comply, but cheap films with a true black base are technically prohibited.¹

Side Mirrors on Tinted Vehicles

Any vehicle with aftermarket window film must have exterior side mirrors on both the left and right. The requirement applies to all tinted vehicles, not just those with dark rear windows, and the mirrors must give a clear view of at least 200 feet behind the vehicle.³ Most modern vehicles already have dual mirrors from the factory, so this mainly matters for older trucks or specialty vehicles built with only a driver-side mirror.

Medical Exemption

If you have a medical condition requiring protection from sunlight, Washington allows darker tint on all windows and on the top six inches of the windshield. You need written verification from a licensed physician stating that the tint is medically necessary.¹

There is no state form and no agency approval step. Your doctor writes the letter, and you carry it in the vehicle at all times. When an officer stops you, you present it on request.³

The statute does not specify which conditions qualify, and it does not require the letter to name a specific VLT level or identify the vehicle by plate number. The operative language is protection from sunlight for physical or medical reasons. Conditions like lupus, melanoma risk, and severe photosensitivity are common justifications, but the call is the physician’s. Keeping the letter in the vehicle every time you drive is essential; without it, an officer has no way to distinguish your car from one with illegal tint.

Penalties for Illegal Tint

Driving with window film that violates RCW 46.37.430 is a traffic infraction, not a criminal offense. It won’t lead to arrest and won’t appear on a criminal record.¹

The base penalty for an unscheduled traffic infraction in Washington is $48 before statutory assessments. Those assessments roughly double or triple the base amount depending on the jurisdiction, so the total cost of a tint ticket typically lands well above $48. Officers measure VLT with a photometer pressed against the glass, and that reading is the evidence attached to the citation.

Paying the fine and keeping the illegal film is a losing strategy. You can be ticketed again at every subsequent traffic stop, and each citation carries its own penalty. Removing or replacing the non-compliant film is the only way to stop the cycle. Some courts may issue a notice to correct the violation, giving you a window of time to bring the vehicle into compliance before the full fine applies.

1
Washington State Legislature. Revised Code of Washington 46.37.430 – Safety Glazing Sunscreening or Coloring
2
National Highway Traffic Safety Administration. Interpretation ID 17440drn – Standard No. 205
3
Washington State Patrol. Vehicle and Equipment Requirements