RCW 46.61.507: Arrest upon driving under the influence or being in physical control of vehicle under the influence, notation required if child is present—Arrest upon drug or alcohol-related driving offense, child protective services notified if child is present and operator is child's parent, guardian, or custodian.

(1) In every case where a person is arrested for a violation of RCW 46.61.502 or 46.61.504, the law enforcement officer shall make a clear notation if a child under the age of sixteen was present in the vehicle.

(2) A law enforcement officer shall promptly notify child protective services whenever a child is present in a vehicle being driven by his or her parent, guardian, legal custodian, or sibling or half-sibling and that person is being arrested for a drug or alcohol-related driving offense. This section does not require law enforcement to take custody of the child unless there is no other responsible person, or an agency having the right to physical custody of the child that can be contacted, or the officer has reasonable grounds to believe the child should be taken into custody pursuant to RCW 13.34.050 or 26.44.050.

(3) For purposes of this section, "child" means any person under sixteen years of age.