Any public entity may place blue reflective pavement markers in any highway, street, or road for marking fire hydrant locations and water supply locations. These blue reflective pavement markers shall not be used for any other purpose. This section shall not apply to freeways or freeway ramps.
A public entity shall not place blue reflective pavement markers on a state highway unless it first obtains an encroachment permit from the Department of Transportation.
Ca. Health and Saf. Code § 13060