The short version
Rodent control in Louisiana has to survive the weather as well as the rodents. About 61 inches of rain a year can flood ground harborage and move rats toward and up into buildings, while winter lows near 43F are too mild to do much thinning. Seal every quarter-inch gap with metal, then trap until captures stop.
- Heavy rain can flood burrows and push rats toward buildings.
- Mild winters near 43F mean breeding slows rather than stopping.
- Use metal for sealing, since humidity and gnawing defeat softer materials.
- Standing water is a rodent attractant and a leptospirosis factor.
- Disinfect droppings, give them five minutes, then wipe them up.
For homeowners hearing movement overhead or finding droppings in a cabinet, renters documenting a problem, and anyone running a kitchen, market or stockroom where droppings become a compliance issue quickly. It is also for people who have paid for monthly service for a year and still see evidence, which usually means the building was never sealed.
What to look for
Norway rats stay low, digging burrows against foundations, under sheds and near waste storage. House mice live entirely inside walls and cabinets and need almost nothing to keep going. The climate keeps all three working. Summer highs near 92F with humidity around 76 percent mean vegetation stays thick and moisture is never a limiting factor. Roughly 61 inches of annual rain can saturate the ground again and again, and rats in flooded burrows respond by moving up and in: into raised spaces, attics, sheds and outbuildings. Then a mild winter, with lows only reaching about 43F, lets the population carry over instead of crashing. That is why Louisiana rodent work is judged by how well the building is sealed rather than by what season it is. Three rodents matter. Roof rats climb: fence lines, vines, cables and limbs lead them to a roof edge, and they nest in attics, soffits and above ceilings.
- 1Fast movement across a ceiling within an hour or two of dark.
- 2Droppings on top of ductwork, a water heater or high shelving.
- 3Greasy rub marks along a rafter, joist or the top of a wall plate.
- 4Chewed screening at a vent or a gnawed corner where soffit meets fascia.
- 5Burrow holes in soil beside a shed, slab or waste enclosure after heavy rain.
- 6Nesting material and droppings in a stored boat, trailer or vehicle.
- 7A sour ammonia smell in a closed storeroom or under a raised floor.
Why it’s worth acting soon
- Mild winters let populations carry over instead of dying back.
- Chewed wiring above ceilings and in stored equipment is a fire and repair risk.
- Rat urine in wet ground and standing water is how leptospirosis reaches people.
- Salmonellosis and rat-bite fever also appear on the CDC list of rodent-borne illnesses.
- Humid conditions make soiled insulation deteriorate faster once it is fouled.
- Droppings in a food business become a regulatory problem within a single inspection.
Treatment options and typical costs
Exclusion sealing
Quoted after inspection
Openings a quarter inch and wider are closed from grade to roofline with hardware cloth, sheet metal and steel wool packed behind sealant. In this climate the material choice matters as much as the coverage, because humidity and gnawing together make short work of foam, screen mesh and unbacked caulk.
- Time
- Depends on the building and the openings found
- Best for
- Any property that has seen rodents more than once
Trapping program
Quoted after inspection
Traps are set on established runways in ceilings, along walls and near burrow entrances, then checked and moved over several visits until captures stop. Placement beats bait selection, since rats repeat routes nightly. Ask how many return visits the quote covers and who removes what is caught.
- Time
- Runs until no new captures turn up
- Best for
- Clearing the animals already using the building
Exterior and burrow work
Quoted after inspection
For Norway rats the job runs outdoors: mapping burrows, collapsing them, moving waste containers onto a clean hard surface, cutting back cover along walls and eliminating standing water. Ask how any stations are anchored and what keeps pets and other animals out of them.
- Time
- Recurring while burrows reopen
- Best for
- Ground-level rat activity and wet yards
Cleanup and insulation replacement
Quoted after inspection
Fouled insulation is bagged out, surfaces disinfected and new material installed. The CDC sets the sequence: ventilate 30 minutes, wet everything with a bleach solution of about 1.5 cups per gallon, allow five minutes, then wipe up. Dry sweeping and vacuuming are not part of it.
- Time
- Depends on how much insulation is fouled
- Best for
- Attics and storage areas with heavy droppings
Prices are typical published ranges. Ask what’s included before you compare quotes.
Clutter gives mice cover. Keeping stored fabric in lidded bins and off the floor takes away the nesting spots they like best.Which rodents you meet in Louisiana, and where.
UC IPM puts their output at three to five litters a year with up to eight young each, and a mild winter here lets that continue rather than pausing. Norway rats work the ground. Their burrows are open holes about the width of a golf ball in soil beside foundations, sheds and waste storage, and UC IPM reports four to six litters a year with 20 or more young weaned per female. House mice are the interior species, nesting in wall voids and cabinet backs and living on crumbs and condensation. The distinction decides your inspection. Overhead noise means ladder work and roofline sealing. Holes in wet soil mean burrow control and sealing at grade. Droppings in a drawer mean interior trapping and quarter-inch gaps. LSU AgCenter's guide treats three species together, and each one lives at a different height, which is the fastest way to sort out what you have. Roof rats are the climbers. Vines, fence lines, cables and overhanging limbs all lead to a roof edge, and once inside they nest in attics, soffits and above ceilings, coming down at night to feed.
What 61 inches of rain does to rodent movement.
What is dry and close by is usually a building: a raised floor, a shed, a garage, a slab edge, or the interior itself through a gap at grade. That is why activity can seem to appear during or right after a wet stretch. The population did not appear that week. It was living outdoors and the water moved it. Two things follow from that. First, drainage is pest work: standing water, clogged gutters, low spots and constantly damp ground under a structure all make the property more attractive and more likely to push animals inside. Second, the sealing has to be done before the rain rather than in response to it. A building closed to a quarter inch does not care how wet the yard gets. Rainfall is the most underrated driver of rodent behavior in Louisiana, and it explains why problems seem to appear suddenly. Norway rats live underground. When the ground saturates, and with roughly 61 inches falling in an average year it saturates often, burrow systems flood and the animals have to relocate.
A good inspection starts outside at ground level: door thresholds, the joint between siding and foundation, and anywhere a pipe or cable enters.Standing water, rats and leptospirosis.
Those national numbers are small, and this is not a reason to be frightened of your yard. It is a reason to take standing water seriously as part of rodent work rather than treating it as a separate landscaping issue. Empty saucers and buckets, clear gutters, fix grading that ponds water against a wall, and keep waste containers on a hard surface that can be rinsed. The same logic applies to cleanup: wet the droppings, wait five minutes, wipe and bag, and never sweep. In a climate this wet, water is where rodent control and health advice meet. Leptospirosis is the illness that connects them. Rats shed the bacteria in urine, it survives in water and damp soil, and people are exposed through contact with contaminated water, particularly through cuts or mucous membranes. CDC surveillance recorded 21 US cases through week 13 of 2026 against 22 in the same stretch of 2025, with separate and much higher counts in Puerto Rico, and rodents appear on the agency's list of carriers.
Sealing that survives Louisiana weather.
Quarter-inch hardware cloth over vents and openings, sheet metal flashing at gaps and roof edges, and steel wool packed into irregular voids and then sealed over. Fasteners should be galvanized or stainless, because in 76 percent humidity ordinary screws rust and the patch loosens. Ask any provider which materials they plan to use at each opening, and ask what the warranty says about failures. The answer tells you a great deal. A crew that talks about hardware cloth, flashing and fastener choice is doing exclusion. A crew that talks about foam is doing a temporary patch. A lot of exclusion work fails here for reasons that have nothing to do with rodents, so it is worth knowing what to ask for. Expanding foam is a common shortcut and among the least durable. Rodents gnaw it easily, and heat and moisture degrade it. Silicone or acrylic sealant used alone has the same problem: nothing about a bead of caulk stops teeth. Fiberglass window screen over a vent does not stop a determined rat. What holds up in Louisiana is metal.
How to compare two rodent proposals.
A good answer includes a re-inspection rather than an open-ended monthly plan. Third, cleanup. Removing fouled insulation, disinfecting and reinstalling may be quoted separately and can be the largest line. Ask whether it is in or out so you are comparing the same job. Fourth, the warranty. How long, what does it cover, does it require a monthly contract to stay valid, and does it survive a sale of the house? Then get everything in writing after an inspection and choose on scope, not on the headline number. Once you have two quotes, resist the urge to compare the totals first. Compare the work. Start with the entry-point list. Does the proposal name specific openings with locations and materials, or does it describe service in general terms? Only the first came from a real inspection, and only the first can be checked afterward. Next, the visit count. Trapping can take weeks, so find out how many returns are included and what happens if activity has not stopped by then.
What affects the price
- How far activity has spread across the building and the grounds.
- The number of openings found and whether they sit at grade or at a roof edge.
- Dense vegetation or standing water that has to be dealt with before sealing.
- Whether soiled insulation removal and replacement is inside the quoted scope.
- How many follow-up trapping visits are included before charges resume.
- Whether burrow work and drainage fixes are in the price or separate.
- Warranty terms on the exclusion work, including length and what voids it.
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What is your biggest concern about rodents in your home?
When to call for help
Call as well if something has died inside a wall or ceiling, since in this heat and humidity that becomes an odor and fly problem quickly. In any food business, treat droppings in prep or storage as something to act on immediately rather than at the next scheduled visit. Bring in help when the noise is overhead rather than at floor level, when droppings appear in more than one area, or when burrows reappear after every heavy rain. Roofline sealing is ladder work and it has to be right the first time, because a single missed opening keeps a roof rat population supplied.
What you can do yourself
The sealing is the part worth paying for. Finding every quarter-inch gap along a soffit run and around a foundation means ladder work, crawling, and knowing which materials survive Louisiana humidity. Trapping in a ceiling is also a commitment, since it means going back up daily, and it is easy to lose momentum. Do the yard, the water and the food storage; get help with the envelope. There is useful work you can do without hiring anyone. Cutting vines and limbs back so nothing bridges to the roof removes the route roof rats prefer. Clearing standing water from saucers, buckets, low spots and clogged gutters takes away a resource that matters even in a wet climate. Moving pet food and pantry goods into hard containers and fitting metal sweeps on doors are quick wins.
Where you live matters
All that water can flood burrows and moves Norway rats toward buildings, while dense vegetation gives roof rats a route to the roofline. Across the cities we track, including New Orleans, Baton Rouge, Shreveport, Lafayette and Lake Charles, summer highs reach about 92F, humidity runs near 76 percent, and annual rainfall averages roughly 61 inches. Louisiana combines heavy rain with high humidity, and rodents benefit from both. With a median home value near $185,000 in the cities we cover, and humidity that punishes anything soft used to plug a hole, the sensible approach in Louisiana is to seal with metal, remove standing water, and treat exclusion as maintenance you check rather than a one-time purchase. Winter lows only fall to around 43F, so populations persist rather than crashing.
Simple ways to keep rodents away
- Trim vines, limbs and hedges so nothing touches or overhangs the roof.
- Screen vents with quarter-inch hardware cloth rather than insect mesh.
- Seal soffit and fascia seams and any point where a line enters the wall.
- Clear standing water from saucers, buckets, gutters and low spots weekly.
- Keep waste in hard bins with tight lids on a clean, hard surface.
- Store pet food, birdseed and bulk rice in sealed hard containers.
- Keep firewood, lumber and yard debris off the ground and away from walls.
- Check stored boats, trailers and vehicles for nesting before using them.
Before you call, sketch where you have seen droppings or heard noise and measure any gaps you found. It makes the first visit faster and the quotes comparable.Did you know?
Puerto Rico recorded 46 leptospirosis cases through week 13 of 2026, more than double the 21 counted across U.S. states.
Norway rats can wean 20 or more young a year, spread across four to six litters.
Murine typhus and Lyme disease are on the CDC list of illnesses linked to rodents indirectly.
Questions people ask
Why do rats show up after heavy rain in Louisiana?
With roughly 61 inches of rain a year, saturated ground can force Norway rats out of underground harborage, and they move toward whatever is dry: raised floors, sheds, outbuildings and the base of houses. A wet week can be when a homeowner first hears activity that has actually been building for months. Often because their burrows flood.
Do rodents die back over the winter here?
Median winter lows across Louisiana sit near 43F, which slows activity without eliminating it, so the population carries over into spring rather than resetting. That is the practical difference from a northern state, and it is why a problem left over the cool months usually returns larger rather than resolving on its own. Not really.
Is leptospirosis something to worry about in Louisiana?
CDC surveillance counted 21 US cases through week 13 of 2026 against 22 in the same period of 2025, with rats named as a key urban reservoir. The bacteria spread through water and wet ground contaminated by rat urine, so removing standing water is a health step as well as a pest one. It is uncommon, but worth understanding in a state as wet as Louisiana.
What sealing materials actually last in this humidity?
Hardware cloth, sheet metal flashing and stainless or galvanized fasteners hold up, and steel wool packed behind sealant fills irregular gaps. Expanding foam, silicone alone and fiberglass window screen all fail here, either from gnawing or from moisture and heat working on the material. Metal ones, which is not a small point in Louisiana.
How small does an opening have to be to keep rodents out?
Rats need more but will chew a smaller hole until it fits. That standard is why exclusion work looks like small metal patches and screened vents rather than a bead of sealant along a seam. Under a quarter inch, which the CDC compares to a pencil width, since that is enough for a house mouse.
How do I clean droppings safely?
Then wet the droppings with a bleach solution of about 1.5 cups per gallon of water, let it soak five minutes, and wipe up with paper towels while wearing gloves. The CDC advises against sweeping or vacuuming dry droppings, which puts particles into the air. Ventilate the space for 30 minutes with nobody inside.
Is bait enough if I cannot afford full sealing?
In this heat it also risks a rat dying inside a wall or ceiling. If the budget is tight, seal the worst openings first and expand the work rather than switching to bait. It buys time and nothing more. Bait lowers the number of animals present while every opening stays available, so the building refills from outside.
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The facts in this article come from the public sources listed above. Every home is different, so ask the company you talk to about pricing and what’s included. Published by Rodent Exterminator · Updated October 11, 2026 · How we write these guides