Urinating in public is illegal in every state. Defendants may be charged under a law that specifically criminalizes the act, or the prosecutor may allege that the defendant presented a public nuisance or is guilty of disorderly conduct. A harsher approach is to charge defendants with indecent exposure or public lewdness, which are crimes that may require convicted defendants to register as a sex offender.
Many city and county criminal ordinances also prohibit public urination. A typical ordinance might prohibit urination “on any street, sidewalk, alley, plaza, park, beach public building or public facility, or any place open to the public or exposed to public view.” An ordinance with this kind of wording prohibits urination even on private property, if it’s visible from a public place. source