In New York and New Jersey, the most common nuisance snake species include the eastern garter snake, northern water snake, and eastern rat snake. While these snakes are generally harmless to humans, they can still cause concern when found in or around homes. Damage they may cause includes frightening residents, potential bites if provoked, and sometimes preying on small pets or birds' eggs. Signs of infestation include sightings of snakes in or around the property, shed skins, or snake nests. Treatment typically involves sealing entry points to prevent snakes from entering buildings, removing potential hiding spots like tall grass or debris piles, and using snake repellents or traps in severe cases. It's important to identify the species correctly and handle them with care, as many snake species are beneficial for controlling rodent populations.