The short version
Rodent control in Charleston, South Carolina centers on roof rats, which nest in attics and trees year-round in this humid coastal city. Since February 1, 2025, the strongest anticoagulant baits are limited to certified applicators statewide, so effective work leans on sealing roofline and foundation gaps, snap trapping inside, and careful cleanup rather than heavy poisoning.
- Roof rats, not mice, are the dominant rodent in many coastal South Carolina properties.
- Four second-generation anticoagulant baits became restricted-use statewide on February 1, 2025.
- Exclusion and trapping now carry most of the load in Charleston rodent work.
- Activity runs all year here, with a noticeable surge in fall.
- Older buildings need gap sealing at rooflines, chimneys and utility entries, not just bait.
This page is for Charleston homeowners hearing scratching overhead, renters finding droppings in a kitchen, and landlords managing older properties with repeat activity. It is also useful for restaurant and food business owners who need a clear sense of what a professional rodent program should include under South Carolina's current bait rules.
What to look for
The roof rat is the rodent that defines Charleston-area work. Clemson University researchers monitoring rodents on nearby Kiawah Island recorded only roof rats, with mice largely absent, which tells you how strongly coastal conditions favor this species. Roof rats climb trees, utility lines and downspouts, then enter at soffits, roof vents, chimney flashing and gaps in older trim. They prefer to nest above ground, so you usually hear them before you see them. The climate keeps them going. With summer highs around 90F, winter lows near 39F and 73 percent average humidity, there is no cold season to slow breeding, and 51 inches of yearly rain keeps vegetation thick and fruit and seed plentiful. Norway rats are the second concern, burrowing along foundations, under slabs and around dumpsters, and the city's 20-foot elevation means saturated soil after heavy rain can push them out of burrows and into structures. House mice round out the picture in kitchens and storage areas. Activity runs year-round, but fall usually brings a surge as cooler nights send more animals looking for shelter.
- 1Scratching or running sounds in the attic or between floors, loudest in the hours after dark.
- 2Spindle-shaped droppings with pointed ends in the attic, on top of cabinets or along shelf edges.
- 3Half-eaten fruit, citrus rinds or nut shells stashed in attic corners or behind appliances.
- 4Dark greasy rub marks on rafters, pipes and the tops of walls where rats run repeatedly.
- 5Gnawed wiring, chewed AC line insulation or damaged ductwork found during service visits.
- 6Burrows near foundations, under steps or beside trash areas, which point to Norway rats.
- 7Pets staring at or pawing at one spot in a ceiling or wall.
Why it’s worth acting soon
- Roof rats raise three to five litters a year of up to eight young each, according to UC IPM.
- Chewed wiring in attics and wall voids is a fire risk that may not show until something fails.
- Droppings and urine can spread illnesses the CDC lists, including leptospirosis and salmonellosis.
- Soiled attic insulation loses its value and typically needs removal and replacement.
- The longer rats stay, the more established their routes become, making exclusion harder and trapping slower.
Effective February 1, 2025South Carolina second-generation anticoagulant restrictionClemson University At least 70 percentKiawah Island accounts that moved off second-generation baitsClemson University 3 to 5, up to 8 young eachRoof rat litters per yearUC IPM Treatment options and typical costs
Exclusion and repair
Quoted after inspection
Every opening around the roofline, chimney, vents, utility lines and foundation gets closed with hardware cloth, sheet metal, sealant or mortar. In historic Charleston buildings, this often means working with fragile trim and old flashing. It is the core of effective roof rat work, especially now that the strongest baits are restricted in South Carolina.
- Time
- One to several visits depending on building size and condition
- Best for
- Roof rats in attics and any recurring problem
Snap trapping
Quoted after inspection
Rat-sized snap traps are placed along rafters, beams and runways, baited with nuts, dried fruit or peanut butter, and checked on a schedule. Trapping removes the rats already inside without poison, so there is no risk of a dead rat decaying in a wall void or of a hawk or bobcat eating a poisoned carcass outdoors.
- Time
- Several weeks of follow-up visits
- Best for
- Rats already established in attics or wall voids
Exterior bait stations
Quoted after inspection
Tamper-resistant stations placed around a building's perimeter can help reduce outdoor rat pressure. Under South Carolina's 2025 rule, brodifacoum, bromadiolone, difethialone and difenacoum are sold only to certified applicators, so ask which active ingredient the provider plans to use and why. Many coastal accounts now run with little or no second-generation bait.
- Time
- Ongoing monthly or quarterly service
- Best for
- Commercial properties and sites with heavy outdoor activity
Sanitation and cleanup
Quoted after inspection
Removing nests, droppings and soiled insulation, then disinfecting surfaces with CDC methods: ventilate 30 minutes, soak with 1.5 cups of bleach per gallon, wait 5 minutes, then wipe. Cleanup also includes removing food sources like fallen fruit and open bird seed that keep rats coming back.
- Time
- One day for most attics
- Best for
- Homes after a long-running infestation
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.What South Carolina's 2025 rodenticide rule means for your home.
Dealers now need a license to sell them, sales are limited to certified commercial, noncommercial and private applicators, and records must be kept. Clemson's Department of Pesticide Regulation issued the rule because of the high potential for harm to non-target wildlife. For a Charleston homeowner, the practical effect is that the strongest baits are no longer on store shelves. Over-the-counter options are more limited, and many local providers have shifted toward exclusion and trapping as their main tools. That shift tends to produce better long-term results anyway. Poison kills rats that are already present, but it does nothing to stop new ones from moving in through the same gaps. Exclusion closes those gaps, and trapping clears out the rats already inside without the risk of a rat dying in a wall. When you talk to a provider, ask how they plan to work within the rule and what their exclusion plan includes. On February 1, 2025, South Carolina restricted four second-generation anticoagulant rodenticides: brodifacoum, bromadiolone, difethialone and difenacoum.
Roof rats on the coast: what a Clemson study found.
That matches what many coastal property owners experience. The roof rat is the main structural rodent along this stretch of coast. The same work turned up a wildlife problem. Second-generation anticoagulants were detected in the island's bobcats, and the bobcat population began declining around 2017. Clemson Regulatory Services estimated that at least 70 percent of Kiawah Island accounts voluntarily moved off those baits as a result. For Charleston homes, the lesson is that a roof rat plan built on poison carries costs you do not see. Hawks, owls and bobcats that eat poisoned rats can die too. A plan built on sealing roof and vent openings, cutting back trees and trapping inside the attic solves the problem without that risk, and it lasts longer because it stops new rats from moving in. Clemson University researchers working on Kiawah Island, on the South Carolina coast, found something striking: roof rats were the only rodent recorded in their monitoring, and mice were largely absent.
A metal vent cover with a working flap keeps mice out all winter. Plastic flaps crack in the cold and get chewed open.Sealing a historic Charleston building without damage.
Buildings that date back a century or more often have settled foundations, gaps where old trim has pulled away, chimney flashing that has loosened, and utility lines cut through walls over many decades. The CDC notes that a mouse can use a quarter-inch opening and that rats gnaw small holes wider, so any of these can work. Good exclusion on an older building starts with a careful exterior inspection, often from a ladder or lift. The provider should list every opening and explain how each will be closed. Hardware cloth and sheet metal work well behind trim and in vents. Mortar or masonry patching suits gaps in brick. Steel wool with sealant works for small holes around pipes. Ask how the work will look when it is done. On a historic home, you want repairs that close gaps without obvious changes to visible surfaces. A written list of every sealed opening also helps if activity returns, because it shows exactly what was done and where. Charleston's historic architecture is beautiful, and it is also full of entry points.
A year of rodent activity in Charleston.
With winter lows near 39F, attics and wall voids stay warm enough for breeding all year, so the calendar is more about changing pressure than an on-off season. In January through March, rats already inside keep breeding, and you mostly notice them at night. Spring brings new growth and fruit, and roof rats spend more time outdoors in trees and gardens. Summer, with highs around 90F and frequent rain, is peak outdoor breeding season, and heavy storms can flood Norway rat burrows near low-lying foundations. Fall is the surge. As nights cool in September and October, more rats look for sheltered nesting spots, and attics become the target. This is when many Charleston households first hear scratching overhead. Late summer is the best window for prevention. Trim trees away from the roof, screen vents and close gaps before the fall push starts. An attic check in spring and again in late summer catches problems early. Rats in Charleston do not take the winter off.
Restaurants and food businesses: what a good program looks like.
Norway rats burrow near dumpsters and loading areas, roof rats get in through rooflines and vents, and house mice slip under doors and into storage rooms. A solid commercial program starts with exclusion. Door sweeps, sealed utility entries, screened drains and closed gaps around pipes keep rodents out of the building. Inside, traps or monitoring devices go along walls in storage, prep and dish areas, and the provider should check them on a regular schedule. Under South Carolina's 2025 rodenticide restriction, ask which baits the provider plans to use and whether they are certified for restricted products. Many now limit second-generation baits to exterior stations or avoid them entirely. Ask for a written service log after each visit showing what was found, what was caught and what was fixed. That record helps with health inspections and shows whether the program is working. A good provider will also point out sanitation issues like grease buildup or dumpster lids left open. Charleston's reputation for cuisine means a lot of commercial kitchens, and kitchens attract rats.
What affects the price
- The age and condition of the building, since older trim, flashing and masonry hide more gaps.
- Roof height and pitch, which affect how much ladder or lift work exclusion requires.
- How much attic insulation has been soiled and needs replacement.
- Whether trees and vines need cutting back from the roof to break rat travel routes.
- The number of trapping visits needed to clear an established population.
- Ongoing service for commercial kitchens or multi-unit buildings versus a one-time residential job.
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What's your biggest concern about rodents?
When to call for help
Call a professional when you hear rats in the attic or walls, find droppings in more than one room, or notice chewed wiring. Roof rats enter high on a building, often through openings you cannot safely reach, and they are cautious around new traps, so a few weeks of DIY trapping often stalls. Get help as well if you own an older Charleston property where sealing means working with original trim, chimneys or flashing, or if you run a food business that needs documented service. Under South Carolina's 2025 restriction, a certified applicator is also the only route to the strongest anticoagulant baits, though many providers now lean on exclusion and trapping instead.
What you can do yourself
DIY works for a mouse or two in a kitchen and for basic prevention. Snap traps are cheap and effective, and you can trim trees, pick up fallen fruit, store pet food in sealed bins and close small gaps with steel wool and sealant. Where DIY struggles in Charleston is the roof rat. These rats come in high, avoid new objects for days, and keep returning until every opening is closed. A full exclusion job means checking soffits, vents, chimney flashing and roof valleys, and that usually needs ladders and experience with older construction. The bait question has also shifted. Since February 1, 2025, homeowners in South Carolina can no longer buy brodifacoum, bromadiolone, difethialone or difenacoum products, which limits over-the-counter poison options. That is not a bad thing, given Clemson's findings on wildlife harm, but it does mean exclusion and trapping matter more than ever.
Rodents in Charleston
The 2025 state restriction on second-generation anticoagulants means most Charleston rodent control now leans on exclusion and trapping, an approach Clemson researchers have encouraged for coastal communities. With a median home value near $520,000, protecting historic homes from gnawing damage and contamination is worth the effort. At just 20 feet of elevation, heavy rains can flood burrows and push rats into buildings. The coastal climate keeps roof rats active all year, with summer highs around 90F, winter lows near 39F, 73 percent humidity and 51 inches of rain. A busy restaurant scene means more food waste and more dumpsters, which support Norway rats at ground level. Centuries-old buildings carry more gaps at rooflines, chimneys and foundations than newer construction. Each of those matters for rodents. Charleston is a city of about 155,000 people, founded in 1670 and known for historic architecture, its cuisine and its charm.
Local research
Rodents in Charleston, SC: what the public record shows
Before you compare quotes, it helps to know which rodents actually live in South Carolina, when they are busiest around Charleston, and what the state figures look like. Everything below links to the agency or university page it came from.
Statewide rodenticide restriction
Brodifacoum, bromadiolone, difethialone and difenacoum: dealer license required, sales limited to certified commercial, noncommercial and private applicators, with sales records kept.
Clemson University Department of Pesticide RegulationCoastal rodent found in a Clemson monitoring study
On Kiawah Island a Clemson entomologist reported roof rats as the only rodent recorded, with mice largely absent.
Clemson University Cooperative ExtensionRodent species recorded in South Carolina
- House mouse (Mus musculus) — Enters at 1/4 inch; 5-10 litters per year; eats about 200 small meals a night.
- Norway rat (Rattus norvegicus) — Burrowing rat of basements, sewers and ground floors; tail shorter than head plus body.
- Roof rat (Rattus rattus) — Climber of attics and trees in warm and coastal regions; tail longer than head plus body.
When rodents are busiest around Charleston
Year-round, fall surge. Roof rats dominate Florida, Texas and Gulf Coast attics.
Based on Charleston’s humid subtropical climate profile.
South Carolina is one of the few states with a statewide second-generation anticoagulant restriction, so coastal roof rat work leans on exclusion and trapping.
Rules that apply in South Carolina
For context, nationally
- 1/4 inch (the width of a pencil) — Smallest gap a mouse can enter. CDC
- 890; 35% fatal; 94% west of the Mississippi — Hantavirus cases reported since 1993 (through 2023). CDC
Sources: Clemson University Department of Pesticide Regulation; Clemson University Cooperative Extension; CDC; Pest Notes: House Mouse; Pest Notes: Rats. Figures are quoted as the source prints them. How we check our sources
Simple ways to keep rodents away
- Trim tree limbs, palms and vines so they do not touch the roof or hang over it.
- Screen attic and foundation vents with hardware cloth, since roof rats chew through plastic screening.
- Close gaps around AC lines, cable entries and plumbing with metal mesh and sealant.
- Pick up fallen fruit, nuts and bird seed daily, especially during fall.
- Store pet food and feed in metal or heavy plastic containers with tight lids.
- Keep firewood, lumber and stored items off the ground and away from exterior walls.
- Make sure crawlspace doors and garage doors close tightly with no gaps at the bottom.
- Check attics twice a year for droppings or nests, especially in late summer before the fall surge.
After sealing, a few monitors or unset traps left along the walls tell you whether anything is still getting in before you hear it again.Did you know?
Clemson researchers monitoring rodents on Kiawah Island recorded only roof rats, with mice largely absent.
Second-generation anticoagulants were detected in Kiawah Island's bobcats, and the population began declining around 2017.
Rodents spread some diseases indirectly through their fleas and ticks, including plague, Lyme disease and murine typhus.
Questions people ask
Can I still buy strong rat poison in South Carolina?
Charleston homeowners can still use traps and exclusion, which handle most problems. Clemson researchers documented deaths in animals that ate poisoned rodents, which drove the change. Since February 1, 2025, South Carolina restricts brodifacoum, bromadiolone, difethialone and difenacoum to certified applicators, and dealers need a license and must keep sales records. Not the strongest kinds.
Why do Charleston homes have roof rats more than mice?
Mice still turn up in kitchens, but attic noise in Charleston is usually a rat. Charleston's mild winters, 73 percent humidity and dense trees give roof rats food, cover and easy routes to attics. Coastal conditions favor roof rats.
When are rats worst in Charleston?
Late summer is the best time to seal openings before the fall push. Activity usually surges in fall, when cooler nights push more rats toward attics, and during wet spells when soaked ground drives Norway rats out of burrows. Rats are active all year in Charleston, since winter lows only average about 39F.
Why would a provider choose traps over poison?
On Kiawah Island, Clemson reports that at least 70 percent of accounts moved off second-generation baits after the chemicals turned up in bobcats. Outdoors, predators can be poisoned too. A rat that eats bait may die inside a wall and smell for weeks. Partly because of the 2025 restriction, and partly because poison has real downsides.
How do I safely clean up rat droppings?
Never sweep or vacuum dry droppings. Open the space to air out for 30 minutes, wear rubber gloves, spray the droppings and nest material with a mix of 1.5 cups of bleach per gallon of water, wait 5 minutes, then wipe it up with paper towels and bag it. Follow the CDC method.
How fast do roof rats multiply?
Roof rats produce three to five litters a year with up to eight young each, according to UC IPM. In a Charleston attic, where temperatures stay mild through winter, breeding does not really stop, so a few rats in spring can turn into a large colony by fall if openings stay open.
What should a Charleston restaurant ask a rodent provider?
Ask for a written plan that covers exclusion at doors, drains and utility entries, the type and placement of traps and stations, how often they will be checked, and a service log after every visit. Under South Carolina's 2025 rules, also ask which baits they use and whether they are certified for restricted products.
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Sources (6)
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