Illegal Window Tint in Washington
The films and darkness levels that are actually against the law here, straight from the statute.
The short answer
Tint is illegal in Washington if it lets less than 24% of light through a front side window, reflects more than 35% of light back, is a mirror finish, or is red, gold, yellow or black. Driving on it is a traffic infraction.
Most articles on this subject repeat a number someone half-remembered. This page works from the statute itself — RCW 46.37.430 — and every rule below points at the subsection it comes from.
The four ways tint becomes illegal here
| What | The rule | Where it says so |
|---|---|---|
| Too dark | Under 24% light transmission on any window except the windshield | subsection (5)(a) |
| Too reflective | Over 35% total reflectance | subsection (5)(a) |
| Prohibited material | Mirror finish; red, gold, yellow or black film; spray-on or brush-on liquid film | subsection (5)(g) |
| Layered film | More than a single sheet applied to any one window | subsection (5)(a) |
The colour rule catches people out
Red, gold, yellow and black film are named in the statute as not permitted. Black is the one that surprises people, because "black tint" is how everybody describes dark film in conversation. The statute is talking about the colour of the material, not how dark it is — a normal charcoal-looking film that meets the light transmission limit is fine.
Only one sheet per window
You cannot layer a second film over an existing one to get darker. If there is already film on the glass, it has to come off before new film goes on. This is also why a re-tint on a car with old film is a removal job first and a tinting job second.
The mirror requirement people forget
If film is applied to any window other than the windshield, the vehicle must have outside mirrors on both the left and right, positioned so the driver can see at least 200 feet of road behind through each one (subsection (5)(f)). If you tint a rear window on a vehicle that only has one side mirror, the tint is not legal even if the darkness is.
What actually happens if it is illegal
Subsection (7) makes operating a vehicle with film in violation of this section a traffic infraction. It is not a criminal charge. What it means practically is that you can be stopped and cited for it, and you will have paid twice — once to have the film fitted, once to have it removed.
Enforcement practice varies between agencies and is not something we can promise anything about. What we can tell you is exactly what the statute says, so the decision you make is an informed one.
The exceptions that are genuinely legal
Two real exceptions exist and both are commonly missed. Trucks, motor homes and multipurpose passenger vehicles may go darker than 24% behind the driver (subsection (5)(b)). And a physician's written verification allows a greater degree of light reduction for a driver or passenger who has to be protected from sunlight (subsection (5)(d)).
Questions we get
Is 20% tint legal in Washington?
Not on the front side windows — 20% is below the 24% minimum. Behind the driver it depends on the vehicle: on a car, no; on a vehicle the manufacturer classifies as a truck, motor home or MPV, yes.
Is 5% limo tint legal?
Not on front side windows on any vehicle. Behind the driver it is only permitted on the vehicle classes listed in subsection (5)(b) — which includes many SUVs and trucks.
Is black tint illegal in Washington?
Black is listed as a prohibited film colour in subsection (5)(g). In practice the film sold as ‘black’ by most brands is a neutral charcoal that is not a black-coloured material, but a genuinely black film is not permitted.
Can I put a second layer on to make it darker?
No. Subsection (5)(a) prohibits more than a single sheet on any window.
What is the penalty?
It is a traffic infraction under subsection (7). We cannot tell you what a specific officer or court will do, only what the statute classifies it as.