Rodents After a Storm or Flood: Shore Home Checklist

Floodwater and heavy rain drown or wash out burrows, nests and runways. Rats and mice that survive do not leave the area. They move to the nearest dry, sheltered place, which is often a garage, crawl space, attic or wall void. Storm damage to siding, vents and foundations can hand them an open door at the same moment.

In Little Silver, Seven Bridges Road and Prospect Avenue are known for tidal flooding at high tide, and Hurricane Sandy in October 2012 flooded low bayside streets across Monmouth County. If your lot is low, or backs onto the Shrewsbury River or a stream that feeds it, treat every major storm as a trigger for a rodent check. Do the walk-around within a day or two, not a month later.

Start outside, while the ground is still wet and tracks and fresh dirt show up clearly. Then move inside to the places water reached or where warm, dry storage sits. The goal is to find any new opening and any sign that animals are already in, before they settle in and start nesting.

About 8 percent of borough homes sit directly on the river, and roughly another third sit on streams that connect to it. For those lots, check the side of the house facing the water first, because that is where rats coming off a bank meet your foundation. Look at bulkhead edges, stone or timber retaining walls, and the base of decks, where a washed-out gap can become a tunnel.

Anything that got wet and cannot be dried within a day or so becomes a mold problem and a rodent nesting site. Anything that touched floodwater, or that a rodent has soiled, should be handled with care. Use the table below as a general guide, and follow local guidance for flood-damaged materials.

When you find droppings or nesting material, do not sweep or vacuum it. Our guide to cleaning up mouse droppings safely walks through the gloves, ventilation and disinfectant steps. Wet insulation in an attic or crawl space is a bigger job, and our attic and crawl space cleanup service covers removing and replacing it.

A storm opens the door for rodents. Close it within days, not weeks.

Start with anything a storm could have loosened. Wind and water pry siding, tear vent covers and crack the seal around crawl space doors. A gap only about one quarter inch wide is enough for a mouse, and about one half inch is enough for a rat. Small storm damage is often exactly that size.

• Replace torn foundation and gable vent screens with hardware cloth of one quarter inch mesh.
• Fix loose or missing siding and trim, and fill gaps around pipes and cables with sheet metal, mortar or a durable sealant.
• Repair or replace the crawl space access door so it closes flush and cannot be pushed in.
• Do not rely on foam or steel wool alone, because rodents chew through foam and pull steel wool loose.
• Cap or screen chimneys and dryer vents that the storm loosened.

Sealing is the part that decides whether the animals stay out. Our rodent exclusion work follows the same idea: find every opening, then close each with a material rodents cannot chew. If the damage is extensive, rodent damage repair can rebuild what the storm and the animals took.

Rodent activity after a storm does not always show up on day one. Displaced animals may settle into a new spot, then start to breed and leave clear signs later. Keep a simple log and check the same places each week.

Days 1 to 7.

Look for fresh tracks, new burrows and gnaw marks near damaged areas. Listen for scratching at dusk and at night. Any animal already inside will usually be most active after dark.

Weeks 2 and 3.

Droppings, greasy rub marks along walls, shredded nesting material and a musty smell are the usual next signs. Mice can have a litter in about three weeks, so a small problem can grow quickly. Check garages, basements, attics and the space under the kitchen sink.

Week 4 and beyond.

If you have found nothing after a month, your sealing work may be holding. If you find fresh signs, call. Rats along a waterfront often work their way in from a bank or a stream, and our post on Norway rats in waterfront homes explains what that looks like.

Rodent droppings, urine and nesting material can carry germs, and floodwater can spread them. The CDC lists salmonellosis, leptospirosis and rat-bite fever among rodent-linked concerns. Wear gloves and a mask when you clean, wash your hands often, and keep children and pets away from the area.

If anyone develops a fever, stomach illness or another concern after cleaning up, talk to a physician and mention the exposure. Do not handle live or dead rodents bare-handed. If the job is large, or the space is soaked and contaminated, hire a professional rather than doing it yourself.

A technician starts with an inspection of the outside, then the crawl space, basement, garage and attic. The aim is to tell whether animals are already inside, where they entered and what the storm changed. That tells us whether the job is trapping, sealing, cleanup or all three.

Trapping removes animals that are already indoors, and sealing keeps new ones out. Doing only one leaves the problem half solved. For animals in the house, rodent trapping and removal is the first step, and sealing follows once the space is clear.