Answer: If you do not have permission - YES it's illegal. If you have permission - NO it's not illegal. This is the way that it works in most places around the world. The reason that this is a confusing question is because the word 'Graffiti' has ambiguous meanings.

Does graffiti have to be illegal?

Section 594 of the California Penal Code is the guiding law against vandalism and graffiti. In general, a person is guilty of vandalism if they deface, damage, or destroy property, which is not their own. ... With this in mind, as long as artists seek authorization from owners, the graffiti on the wall is 100% legal.

Why is graffiti considered illegal?

Graffiti is illegal because it is considered a form of vandalism or criminal mischief, according to Graffiti Hurts. Graffiti artwork is tagged on buildings without the owners' permission, amounting to destruction of private property.