It's the Law: Required Equipment

Sound-Producing Devices (625 ILCS 45/4-4 and 45/4-8)

On Illinois state waters, all motorized vessels must have a mouth-, hand-, or power-operated whistle or other device capable of producing a blast that is two seconds or more in duration and audible for at least one-half mile.

No vessel may be equipped with a siren, except law enforcement and emergency vessels.