Pest control in Delaware County, PA: older homes, mosquitoes and local help
Updated · KeystoneProGuide editorial team
What should you know about pest control in Delaware County?
That it is an older, closely built county, and that it has a county health department to call. The county describes itself as the fourth most populous in the state with the third smallest land area, spread across forty-nine municipalities. A company working here needs the same state pesticide license as anywhere in Pennsylvania.
How do older homes affect pest problems?
The Census Bureau estimates that 22.1 percent of the county's 229,715 housing units were first built in 1939 or earlier, close to the state's 25.0 percent and well above its suburban neighbors, and only 3.5 percent were built since 2010. The CDC says a mouse can fit through a hole the width of a pencil, and lists the places to look: around pipes under sinks and to water heaters and furnaces, around utility lines, between the foundation and the ground, and in the attic, basement or crawl space. Small holes can be filled with steel wool held in place with caulk; larger ones need metal, cement or hardware cloth.
Age also matters for termites. Penn State Extension says most Pennsylvania infestations are in basements and the timbers just above the cellar walls, and that termites favor warm spots around furnaces, chimneys and water heaters. Ask any inspector to show you what was checked in the cellar. Penn State also warns that wood in contact with the soil, or embedded in a concrete floor, is especially at risk.
Does anyone spray for mosquitoes here?
The state does, when testing calls for it. On July 16, 2026, the Department of Environmental Protection sprayed from trucks in Ridley, Darby and Tinicum townships after finding high numbers of mosquitoes capable of carrying West Nile virus. Its advice to residents was to get rid of containers that hold water, drill holes in recycling bins, clean clogged gutters each year, turn over wading pools and wheelbarrows, and keep unused pools chlorinated. For water that cannot be drained, it says Bti products, a naturally occurring bacterium sold in garden and hardware stores, kill mosquito larvae.
The county health department also publishes mosquito and West Nile alerts, including the locations of positive mosquito pools and spraying notices. People who have joined the state's pesticide hypersensitivity registry are owed notice from businesses applying pesticides within 500 feet of their home, work or school.
Who do you call about a health problem?
The Delaware County Health Department, which has a Division of Environmental Health that coordinates responses to public complaints on environmental and public health matters in the county. Its Wellness Line, (484) 276-2100, answers calls and email around the clock, and the environmental health office is at Rosetree 1 on North Providence Road in Media.
About 30.4 percent of the county's occupied homes are rented. A tenant with a pest problem the landlord is not addressing can ask the health department what county rules apply before paying for treatment.
Where do you complain about a company?
To the county's Office of Consumer Affairs, which offers voluntary mediation and takes complaints about home repair, among other things. It refers suspected fraud to the District Attorney or the Attorney General. The office is in the Government Center Building, 201 West Front Street, Media, and its number is 610-891-4865. A complaint about how a pesticide was applied goes to the state Department of Agriculture.
How do you check a company here?
Use the Department of Agriculture's business license lookup, which can be searched by county, and check the BU license number on the company's vehicles and the technician's card. The state rules are in Pennsylvania's rules for exterminators, and companies serving the county are on the Delaware County pest control page.
Sources
- 2020-2024 ACS 5-Year Narrative Profile: Delaware County, Pennsylvania, U.S. Census Bureau
- 2020-2024 ACS 5-Year Narrative Profile: Pennsylvania, U.S. Census Bureau
- Your County at a Glance: History, Delaware County
- Division of Environmental Health, Delaware County Health Department
- Department of Environmental Protection to Conduct Mosquito Control in Delaware County, Pennsylvania Department of Environmental Protection
- Consumer Affairs/Weights & Measures, Delaware County
- How to Seal Up to Prevent Rodents, U.S. Centers for Disease Control and Prevention
- Eastern Subterranean Termites, Penn State Extension
- Pesticide Application Businesses, Pennsylvania Department of Agriculture
- Pesticide Hypersensitivity Registry, Pennsylvania Department of Agriculture