Bees in Walls and Homes: Facts and Statistics

Colony size

How big a colony in a wall gets

A swarm that moves into a wall starts small. Given a season or more, it fills the space between studs with comb, brood and stored honey.

1. UC IPM says a well-established honey bee colony may have up to 100 pounds of honey (2012). (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
2. UC Riverside entomologists say a colony killed in a wall can leave up to 10 pounds of dead bees, several more pounds of developing larvae, and up to 100 or so pounds of honey. (Source: UC Riverside Department of Entomology, Unwanted Honeybees)
3. NC State Extension says there may be as much as 40 pounds of honey within a wall by the end of spring. (Source: NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024)
4. Texas A&M AgriLife Extension says a healthy colony can have as many as 60,000 workers (2017). (Source: Texas A&M AgriLife Extension, Honey Bees In and Around Buildings (ENTO-080), 2017)
5. The University of Arizona says a full-sized colony at peak season contains an average of 60,000 bees, and well-managed hives can hold up to 80,000. (Source: University of Arizona, Africanized Honey Bee Information Sheet 5)
6. A swarm looking for a new cavity can contain 5,000 to 20,000 bees, according to UC IPM (2012). (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
7. Seeley (1977) described a typical natural swarm as about 2 kg, or roughly 15,000 bees. (Source: Seeley, Behavioral Ecology and Sociobiology, 1977)
8. LSU AgCenter notes colonies in walls can build two or three layers of comb per stud section. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
9. Wax is costly to make: researchers cite a ratio of about 7 units of honey consumed per unit of wax produced (Bailey et al., 2023, citing Weiss 1965 and Hepburn et al. 1984). (Source: Bailey, Marting & Smith, Insectes Sociaux, 2023)
10. UC Riverside warns that an established colony left in place will continue to grow, build more comb, store more honey and become more defensive. (Source: UC Riverside Department of Entomology, Unwanted Honeybees)

The 40-pound figure (NC State) describes a colony by the end of one spring; the 100-pound figures (UC IPM, UC Riverside) describe well-established colonies. Both are upper bounds, not averages. Real amounts depend on cavity size, colony age and nectar flow.

Nest sites

Where bees nest in buildings, and why

Scout bees look for a dark, dry cavity of a certain size with a small, defensible entrance. A wall bay, soffit, attic corner or floor void often fits that description.

1. In nest-box tests, swarms were more likely to choose a 40-liter cavity than a 10- or 100-liter one (Seeley & Morse 1978, as summarized by Visick & Ratnieks 2023). (Source: Visick & Ratnieks, Journal of Insect Conservation, 2023)
2. The same tests found swarms preferred a south-facing entrance of 12.5 cm2 over a north-facing one and over a 75 cm2 entrance (Seeley & Morse 1978). (Source: Visick & Ratnieks, Journal of Insect Conservation, 2023)
3. Swarms preferred cavities 5 meters above ground over ones 1 meter up (Seeley & Morse 1978). (Source: Visick & Ratnieks, Journal of Insect Conservation, 2023)
4. Seeley and Morse (1978) also found swarms preferred entrances at the bottom of a cavity rather than the top, and their data suggested a preference for previously inhabited cavities. (Source: Seeley & Morse, Insectes Sociaux, 1978)
5. In a sample of 49 natural nests, Seeley (1977) found a modal cavity volume of about 35 liters, with a range of 12 to 443 liters. (Source: Seeley, Behavioral Ecology and Sociobiology, 1977)
6. About 80% of the natural nests Seeley measured fell between 20 and 100 liters (1977). (Source: Seeley, Behavioral Ecology and Sociobiology, 1977)
7. UC IPM says honey bees will nest in cavities of at least 4 gallons but prefer cavities around 9 gallons (2012). (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
8. UC IPM says bees prefer dark cavities with an easily defended entrance at least 9 feet from the ground. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
9. MAAREC extension guidance puts the preferred cavity at 40 liters (range 20 to 100) and the ideal height at about 3 meters (9 feet), with southward-facing exposures favored (2004). (Source: MAAREC, Basic Bee Biology for Beekeepers (Pub. 1.4), 2004)
10. Wild colonies have mainly been found using cavities between 15 and 80 liters, with entrances of roughly 10 to 60 cm2 (Visick & Ratnieks 2023, citing several earlier studies). (Source: Visick & Ratnieks, Journal of Insect Conservation, 2023)
11. LSU AgCenter lists common wall entry points as a fallen knot hole, broken mortar, and gaps between brick and siding. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
12. UK researchers who surveyed wild colonies in trees suggest there are likely many more wild colonies nesting in buildings and other man-made structures (an estimate, not a count). (Source: Visick & Ratnieks, Journal of Insect Conservation, 2023)

UC IPM's 9 gallons, MAAREC's 40 liters and Seeley's 35-liter modal volume describe roughly the same size cavity. The preference figures come from nest-box tests in New York and may differ for Africanized bees, which the University of Arizona says occupy smaller spaces.

Killed in place

What happens when a colony is killed or sealed in

Killing bees does not remove the nest. The comb, honey, brood and dead bees stay in the wall, and the bees are no longer there to cool and guard it.

1. UC IPM says that when bees are killed and the nest is left, unattended honey can absorb moisture and ferment, run down inside the wall until it meets a ceiling, floor or frame, and seep through the drywall. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
2. UC IPM says dead bees may rot in place and produce a very bad odor. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
3. UC Riverside says that after a kill, combs may melt or fall and honey can seep out through wallpaper and baseboards. (Source: UC Riverside Department of Entomology, Unwanted Honeybees)
4. LSU AgCenter explains that once bees die, stored honey draws moisture from the air and surroundings, which allows fermentation and souring. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
5. The University of Kentucky says wax left in a wall may melt or be riddled by wax moth larvae and begin to leak honey (2019). (Source: University of Kentucky Entomology, Controlling Nuisance Honey Bees (Entfact-606), 2019)
6. Kentucky entomologists add that carpet beetles and other scavenging insects are attracted to killed bee colonies. (Source: University of Kentucky Entomology, Controlling Nuisance Honey Bees (Entfact-606), 2019)
7. Texas A&M AgriLife lists odor from dead bees and fermenting honey, staining, and pests including ants, cockroaches, carpet beetles, wax moths and rodents as problems with large nests (2017). (Source: Texas A&M AgriLife Extension, Honey Bees In and Around Buildings (ENTO-080), 2017)
8. NC State Extension says honey can continue to ferment and discolor and damage walls, and stored honey and dead bees attract ants and cockroaches. (Source: NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024)
9. UF/IFAS warns that nest contents left behind may rot, ferment and leak into the home, and that beetles, ants, cockroaches and flies may move in (2020). (Source: UF/IFAS EDIS, Best Management Practices for Live Bee Removals in Florida (ENY-2052), 2020)
10. LSU AgCenter says honey leaking from a wall can attract ants, wasps and other animals that eat honey. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
11. The Texas Apiary Inspection Service advises against sealing bees in, because they will find a way out, possibly getting loose inside the structure. (Source: Texas Apiary Inspection Service, Honey Bee Removal Informational Document (undated))
12. NC State Extension says plugging the entrance hole is ineffective because the bees will search for another entrance. (Source: NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024)
13. UC Riverside says that if bees have been in a cavity more than a week, not opening the cavity to remove them is asking for trouble. (Source: UC Riverside Department of Entomology, Unwanted Honeybees)

Small hive beetles are a known pest of stored comb, but none of the extension sources reviewed here named them for wall colonies, so they are not listed. Several of these extension sheets also describe insecticide options; they are cited here only for what happens to the nest afterward. UC IPM notes that honey, wax and dead bees from a nest treated with pesticides are contaminated and must be handled as hazardous waste.

Re-infestation

Why new swarms move into the same wall

Old comb smells like a proven home. If comb is left and the entrance stays open, the next swarm season can bring a new colony to the same spot.

1. Texas A&M AgriLife says traces of old comb are highly attractive to bees, and they will reinfest a building unless the nest is removed (2017). (Source: Texas A&M AgriLife Extension, Honey Bees In and Around Buildings (ENTO-080), 2017)
2. UC IPM says the beeswax odor left after removal is highly attractive to future scout bees looking for nest sites, so the site must be sealed. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
3. Ohio State Extension says the odor of honey comb and wax attracts other honey bees and insects (2012). (Source: Ohio State University Extension, Honey Bees in House Walls (HYG-2079), 2012)
4. The University of Kentucky says odors left by a colony can linger for a long time and attract other swarming bees. (Source: University of Kentucky Entomology, Controlling Nuisance Honey Bees (Entfact-606), 2019)
5. The Texas Apiary Inspection Service says that if comb is left behind, another colony or other pests could be attracted to the location. (Source: Texas Apiary Inspection Service, Honey Bee Removal Informational Document (undated))
6. UF/IFAS says an emptied cavity will also be attractive to other swarms, and if left unrepaired, another colony may soon move in (2020). (Source: UF/IFAS EDIS, Best Management Practices for Live Bee Removals in Florida (ENY-2052), 2020)
7. LSU AgCenter recommends washing the wall cavity with ammonia or bleach to remove pheromones that draw bees back. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)

The 1978 Seeley and Morse data suggest, rather than prove, a preference for previously inhabited cavities. Extension sources state the re-infestation risk more firmly, based on field experience.

Heat and structure

Heat, wax and damage to the house

Beeswax softens well below its melting point. A living colony keeps its nest cool; a dead one cannot, and a hot attic or sun-facing wall adds heat.

1. Honey bee (Apis) wax melts between 61 and 63 C as measured by capillary tube methods (Journal of Experimental Biology, 2008). (Source: Buchwald et al., The thermal properties of beeswaxes, Journal of Experimental Biology, 2008)
2. Calorimetry in the same study showed beeswax begins melting at about 40 C. (Source: Buchwald et al., The thermal properties of beeswaxes, Journal of Experimental Biology, 2008)
3. Earlier work cited in the study found that comb loaded with honey, pollen and larvae would exceed the yield strength of beeswax above 40 C. (Source: Buchwald et al., The thermal properties of beeswaxes, Journal of Experimental Biology, 2008)
4. Honey bees actively hold their nest at 34 to 35 C, partly through evaporative cooling. (Source: Buchwald et al., The thermal properties of beeswaxes, Journal of Experimental Biology, 2008)
5. LSU AgCenter says that when stored honey overheats in the wax, the cells can melt and honey runs down the inside and outside of walls. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
6. LSU AgCenter says a wall section with bees is often several degrees warmer than the rest of the wall, which helps locate the nest. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
7. LSU AgCenter warns that spoiled honey soaking into a wall can lead to severe structural damage and an expensive repair bill. (Source: LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002)
8. UC IPM says bees occasionally use water to soften Sheetrock and remove it to expand the nest, and in a few cases open a hole through it. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
9. Ohio State Extension says honey bees living in a building do not cause structural damage, but abandoned comb and honey will melt and foul wall board, siding and insulation. (Source: Ohio State University Extension, Honey Bees in House Walls (HYG-2079), 2012)
10. NC State Extension likewise says honey bees do not cause direct structural damage to buildings. (Source: NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024)

Sources differ on structural damage. Ohio State and NC State say live bees do not damage structure directly. LSU AgCenter says honey soaking into a wall after a colony dies can cause severe damage. Read together, they put most of the risk on comb and honey left behind rather than on bees chewing framing.

Proper removal

How a proper removal is done

Extension sources agree on the basics: open the cavity, take out the bees and every piece of comb, clean up, and close the entry so another swarm cannot use it.

1. UC IPM says taking bees and comb out of a nesting spot requires opening a fairly large hole in some portion of the building. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
2. UC IPM advises that opening the wall is best done by a professional contractor. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
3. The Texas Apiary Inspection Service says all wax comb should be extracted before the cavity is closed, and all entrances sealed at the end of the removal. (Source: Texas Apiary Inspection Service, Honey Bee Removal Informational Document (undated))
4. UC IPM says all holes large enough to insert a pencil that lead to spacious cavities must be sealed. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
5. UC IPM notes that bees can chew out through caulking but will not chew in through it. (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
6. UF/IFAS advises against foam or spray insulation as a patch because bees can chew through it (2020). (Source: UF/IFAS EDIS, Best Management Practices for Live Bee Removals in Florida (ENY-2052), 2020)
7. UC Riverside recommends filling the emptied space with fiberglass insulation and screening openings with mesh under 1/4 inch. (Source: UC Riverside Department of Entomology, Unwanted Honeybees)
8. Texas A&M AgriLife recommends screen mesh smaller than 1/8 inch for openings that must stay open for airflow (2017). (Source: Texas A&M AgriLife Extension, Honey Bees In and Around Buildings (ENTO-080), 2017)
9. Ohio State Extension says trapping bees out of a wall works but takes four to six weeks. (Source: Ohio State University Extension, Honey Bees in House Walls (HYG-2079), 2012)
10. NC State Extension says trapping rarely results in 100% removal of bees. (Source: NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024)
11. Ohio State Extension says removal works best in late winter or early spring, when bee numbers and honey stores are low. (Source: Ohio State University Extension, Honey Bees in House Walls (HYG-2079), 2012)
12. UF/IFAS best practices say to discard comb of unknown history rather than reuse it: when in doubt, throw it out. (Source: UF/IFAS EDIS, Best Management Practices for Live Bee Removals in Florida (ENY-2052), 2020)
13. NC State Extension cautions that wall and ceiling repair may not be included in a removal contract, so homeowners should ask. (Source: NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024)
14. University of Arizona IPM guidance says not to seal holes or fill voids while bees are actively moving in and out (2016). (Source: University of Arizona, IPM for Wild Honey Bees in Community Environments, 2016)

Rules on who may repair walls and what insurance a remover carries vary by state. The UF/IFAS guidance on licensing and contractor repairs applies to Florida law, not California.

Insurance and law

Insurance and who is responsible

Standard homeowners policies are written for sudden losses. Damage from insects, including bees, is usually listed as an exclusion. Check your own policy.

1. The Texas Department of Insurance tells consumers that if rodents and insects chew on a house, the policy won't pay for repairs (2025). (Source: Texas Department of Insurance, What your home policy won't cover, 2025)
2. The same guide says companies won't pay for damage that happens over time, such as rotted boards. (Source: Texas Department of Insurance, What your home policy won't cover, 2025)
3. A Safeco homeowners form filed with Maine regulators lists 'birds, vermin, rodents, insects or domestic animals' among building losses not covered, except glass breakage (2018). (Source: Safeco homeowners Special Provisions form HOM-7100/MEEP, filed with Maine Bureau of Insurance, 2018)
4. In a 2010 North Carolina honey bee case, a state Department of Insurance spokeswoman said the policy language clearly excluded the damage (news report). (Source: WRAL News, quoting the NC Department of Insurance, 2010)
5. In Los Angeles County, bees on your own private property are your responsibility to abate, according to the Agricultural Commissioner. (Source: LA County Agricultural Commissioner/Weights & Measures, Nuisance Bee Complaints)
6. The LA County Agricultural Commissioner cites County Public Health Ordinance 11.02.190, which requires the person controlling a property to abate or remove such a nuisance within a reasonable time. (Source: LA County Agricultural Commissioner/Weights & Measures, Nuisance Bee Complaints)
7. The LA County Agricultural Commissioner states that it does not provide bee removal services. (Source: LA County Agricultural Commissioner/Weights & Measures, Nuisance Bee Complaints)
8. OC Public Works removes or controls hives on county rights-of-way in unincorporated areas, and says hives on private property are for the owner to address. (Source: OC Public Works, Bee/Rodent Services)
9. The Texas Apiary Inspection Service suggests asking a remover about liability insurance, which can protect both parties if there is unexpected damage. (Source: Texas Apiary Inspection Service, Honey Bee Removal Informational Document (undated))

No California Department of Insurance statement on bees was found. The Texas guidance and the Maine-filed policy form show common industry wording; California policies may differ. The WRAL item is a news report quoting a state official, not a regulator's publication.

Southern California

Africanized bees around homes in Southern California

Africanized honey bees look like other honey bees and nest in many of the same places. The difference is how far and how hard they defend the nest.

1. UC ANR says Africanized honey bees can sense a threat from people or animals 50 feet or more from the nest (2002). (Source: UC ANR Publication 8068, Bee Alert: Africanized Honey Bee Facts, 2002)
2. They can sense vibrations from power equipment such as lawn mowers and weed cutters 100 feet or more from the nest, per UC ANR. (Source: UC ANR Publication 8068, Bee Alert: Africanized Honey Bee Facts, 2002)
3. Once provoked, Africanized bees will pursue an enemy a quarter mile or more (UC ANR, 2002). (Source: UC ANR Publication 8068, Bee Alert: Africanized Honey Bee Facts, 2002)
4. UC ANR says Africanized bees nest in small cavities and sheltered areas, including sheds, garages, low decks and spaces under buildings. (Source: UC ANR Publication 8068, Bee Alert: Africanized Honey Bee Facts, 2002)
5. The University of Arizona says Africanized bees are less selective and will occupy a much smaller space than European honey bees. (Source: University of Arizona, Africanized Honey Bee Information Sheet 5)
6. Long Beach's Vector Control Program says Africanized bees swarm frequently to establish new hives and lists attics, porches and utility boxes among nest sites. (Source: City of Long Beach Health, Vector Control Program: Bees)
7. UC IPM says areas colonized by Africanized honey bees include all Southern California counties (2012). (Source: UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012)
8. Africanized honey bees were first detected in California on October 24, 1994. (Source: Contra Costa Mosquito & Vector Control District, Africanized Honeybees FAQ)
9. San Diego County agriculture officials advise sealing openings larger than 1/8 inch in walls and around chimneys and plumbing. (Source: County of San Diego Agriculture, Weights and Measures, Bee Alert fact sheet)

The 50-foot, 100-foot and quarter-mile figures appear in UC ANR Publication 8068 and are repeated by San Diego County and the City of Long Beach. The California Department of Public Health page on this topic could not be retrieved for this review.

Public data

How often local agencies get bee calls

Few agencies publish bee call counts, and most do not remove bees from private homes. The numbers below show the steady share of vector-program calls that involve bees. They do not count every bee problem.

1. Riverside County's Vector Control Program, which serves about half the county's population, responded to 212 service calls in 2023. (Source: Riverside County Environmental Health, Vector Control Annual Report 2023)
2. Bees made up 4% of Riverside County's 2023 vector-control complaints, compared with 89% for mosquitoes. (Source: Riverside County Environmental Health, Vector Control Annual Report 2023)
3. San Bernardino County's Mosquito and Vector Control Program responded to 1,479 service requests in 2016. (Source: San Bernardino County Mosquito & Vector Control Program, Annual Report 2016)
4. Bees and wasps accounted for 9% of San Bernardino County's 2016 vector-control service requests. (Source: San Bernardino County Mosquito & Vector Control Program, Annual Report 2016)
5. Imperial County's Vector Control Program eliminates swarms in unsafe proximity to people but refers bee nests to licensed private companies. (Source: Imperial County Public Health Department, Vector Control services)

These counts cover only calls to county vector programs, which serve limited areas and refer most nests to private companies. They do not measure how many homes have bees in their walls. No Southern California agency reviewed published a count of structural bee removals.

Questions

Frequently asked questions

Keep reading

Related on this site

• Bee hive in your wall? Do this next
• Why you should never spray a hive inside a wall
• Hidden damage bees can cause
• Bees in your attic
• Residential bee removal
• Live bee relocation

How this page was made

Methodology & sources

Every fact on this page was traced to a primary source (a government data release, a university research or extension publication, a professional medical body or a peer-reviewed paper) and checked against the original document. Data years are given where they differ from publication years. Where reputable sources disagree, both figures are shown. Sources are named in plain text next to each fact.

• Bailey, Marting & Smith, Insectes Sociaux, 2023
• City of Long Beach Health, Vector Control Program: Bees
• Contra Costa Mosquito & Vector Control District, Africanized Honeybees FAQ
• County of San Diego Agriculture, Weights and Measures, Bee Alert fact sheet
• Imperial County Public Health Department, Vector Control services
• Buchwald et al., The thermal properties of beeswaxes, Journal of Experimental Biology, 2008
• LA County Agricultural Commissioner/Weights & Measures, Nuisance Bee Complaints
• LSU AgCenter, Removing Bees from Walls (Pub. 2874), rev. 2002
• MAAREC, Basic Bee Biology for Beekeepers (Pub. 1.4), 2004
• NC State Extension, FAQ About Removing Honey Bees from Structures, rev. 2024
• OC Public Works, Bee/Rodent Services
• Ohio State University Extension, Honey Bees in House Walls (HYG-2079), 2012
• Riverside County Environmental Health, Vector Control Annual Report 2023
• Safeco homeowners Special Provisions form HOM-7100/MEEP, filed with Maine Bureau of Insurance, 2018
• San Bernardino County Mosquito & Vector Control Program, Annual Report 2016
• Seeley & Morse, Insectes Sociaux, 1978
• Seeley, Behavioral Ecology and Sociobiology, 1977
• Texas A&M AgriLife Extension, Honey Bees In and Around Buildings (ENTO-080), 2017
• Texas Apiary Inspection Service, Honey Bee Removal Informational Document (undated)
• Texas Department of Insurance, What your home policy won't cover, 2025
• UC ANR Publication 8068, Bee Alert: Africanized Honey Bee Facts, 2002
• UC IPM Pest Notes, Removing Honey Bee Swarms and Established Hives (Pub. 74159), 2012
• UC Riverside Department of Entomology, Unwanted Honeybees
• UF/IFAS EDIS, Best Management Practices for Live Bee Removals in Florida (ENY-2052), 2020
• University of Arizona, Africanized Honey Bee Information Sheet 5
• University of Arizona, IPM for Wild Honey Bees in Community Environments, 2016
• University of Kentucky Entomology, Controlling Nuisance Honey Bees (Entfact-606), 2019
• Visick & Ratnieks, Journal of Insect Conservation, 2023
• WRAL News, quoting the NC Department of Insurance, 2010