The Northern Water Snake (Nerodia sipedon) is a common, non-venomous reptile often found near ponds, lakes, or rivers. These snakes are adept swimmers and seek out food and shelter near residential waterfronts. While they are a natural part of the ecosystem, their presence near homes can cause concern. This guide outlines safe, effective, and humane methods for deterring and managing Northern Water Snakes, focusing on long-term environmental adjustments and physical exclusion techniques.
Confirming the Species Identity
Before attempting deterrence, confirm the snake’s identity for safety. Northern Water Snakes (NWS) are frequently misidentified as the venomous Water Moccasin, or Cottonmouth (Agkistrodon piscivorus). Although the NWS is non-venomous, it will bite defensively if handled, resulting in a painful, non-toxic wound.
The head shape is a primary distinction. The NWS has a relatively slender head that smoothly transitions into the neck. The Cottonmouth possesses a thick, blocky, and triangular head due to its venom glands. The NWS has round pupils, while the Cottonmouth has vertical, slit-like pupils.
Body composition and behavior in water also offer clues. Northern Water Snakes are more slender and typically swim with their bodies submerged below the surface. The Cottonmouth is heavy-bodied and often swims or floats on top of the water with its entire body visible. While the NWS has dark blotches, the adult Cottonmouth is often dark olive to nearly black with hourglass-shaped bands.
Modifying Habitat to Eliminate Attraction
Reducing snake presence involves making the immediate area less appealing by removing their primary resources: food and shelter. Snakes are cold-blooded and require basking spots, so eliminating these areas reduces their presence near structures. Habitat modification focuses on creating an open, clean environment with minimal cover.
Start by clearing debris such as rock piles, stacks of firewood, lumber, and construction waste, as these offer ideal hiding and resting spots. Dense vegetation, especially near the water’s edge, should be trimmed or removed entirely, as it provides a safe corridor for snakes to move undetected. Maintaining a closely mowed lawn adjacent to the shoreline creates an exposed area snakes are reluctant to cross.
Snakes are attracted to properties offering a consistent food supply, which for the NWS includes small fish, frogs, toads, and rodents. Managing these prey populations is an indirect control measure that reduces the snake’s incentive to stay. If the water source is an ornamental pond, consider stocking it with fish that consume amphibian eggs and tadpoles to suppress frog populations.
Installing a fountain, aerator, or waterfall in a pond can also create an environment less favorable to the NWS. These devices introduce constant movement and noise into the water, deterring snakes that prefer still, quiet waters for hunting. This adjustment makes the area less conducive to their stealthy hunting methods.
Physical Barriers and Safe Deterrence Methods
If habitat modification is insufficient, physical exclusion can prevent snakes from entering specific areas like yards or decks. The most effective barrier is exclusion fencing, which must be installed with specific dimensions. The fence should be constructed from galvanized hardware cloth with a small mesh size, ideally no larger than 1/4 inch, to exclude juvenile snakes.
The fencing must be a minimum height of 25 inches above the ground. The bottom edge must be buried at least 4 to 10 inches deep and bent outward in an “L” shape to prevent burrowing. The fence posts should be on the side facing the protected area, leaving a smooth surface on the snake’s side to prevent climbing.
Commercial and natural deterrents are available. Non-lethal funnel traps can be used to capture snakes temporarily for relocation, but glue traps must be avoided due to the inhumane suffering they cause. Any captured snake should be released several miles away in a suitable habitat to prevent its immediate return.
Deterrent Options
- Products containing sulfur can be applied in granulated form around the property perimeter.
- Sulfur is known to irritate a snake’s skin and sensory organs.
- Essential oils, such as peppermint or cinnamon oil, are used as repellents due to their strong odors.
- Repellents must be reapplied frequently, especially after rain, to maintain a consistent barrier.
When to Call Professional Wildlife Services
Contacting a professional is the safest course of action if a snake is discovered inside a home or occupied structure. An untrained attempt at capture can lead to a bite or loss of the snake within the walls. Professionals possess the specialized tools and training necessary to safely remove snakes from enclosed spaces.
If the snake cannot be definitively identified, or if a large number of snakes are present, contact a licensed Nuisance Wildlife Control Operator (NWCO). These experts accurately identify the species and address potential infestations at the source.
Native wildlife species like the Northern Water Snake are often protected by law. Unauthorized capture, relocation, or killing of these animals can be illegal and may result in fines. A licensed NWCO is aware of all regulations regarding handling and relocation, ensuring the removal process is compliant.