10 Pest Hotspots in Commercial Buildings You Might Be Overlooking (And What to Do About Them)

When you think of pest problems in commercial buildings, you probably picture overflowing trash cans or food left out in break rooms. While those are obvious attractants, the most problematic infestations often begin in the least expected places.

At A&B Professional Pest Solutions, we’ve helped property managers, facility directors, and business owners across industries identify hidden threats that go unnoticed until a pest problem spirals out of control. To help you stay ahead, here’s an in-depth look at 10 commonly overlooked pest hotspots in commercial buildings—and how to address them proactively.

1. Floor Drains: A Breeding Ground Below the Surface

Floor drains collect water, soap, and organic debris—especially in commercial kitchens, restrooms, janitorial closets, and utility rooms. These conditions create the perfect habitat for drain flies, phorid flies, cockroaches, and even rodents that can access pipes from the sewer system.

Common signs of activity:

• Small black flies hovering near drains
• A sour or musty odor
• Visible sludge or organic matter around the drain opening

Preventive measures:

• Install drain screens or grates
• Use enzymatic cleaners weekly to remove biofilm
• Schedule regular professional drain flushing

2. Ceiling Tiles and Above-Ceiling Spaces (Plenums)

Damaged or sagging ceiling tiles can indicate hidden leaks from HVAC units or plumbing. The warm, enclosed area above ceiling tiles is often used by rodents as nesting grounds and by insects as travel corridors.

Common pests:

• Mice and rats
• Cockroaches
• Carpenter ants

Preventive measures:

• Replace stained or warped ceiling tiles promptly
• Inspect above-ceiling areas quarterly
• Seal utility penetrations and cable access points with rodent-proof materials

3. Dumpsters and Exterior Waste Disposal Areas

Waste areas are magnets for pests. Rats, flies, raccoons, wasps, and feral animals are drawn to food scraps, spills, and improperly secured containers.

Common risks:

• Disease transmission
• Secondary infestations indoors
• Negative impressions on clients and staff

Preventive measures:

• Clean dumpster pads weekly
• Use dumpsters with tight-fitting lids
• Position dumpsters at least 50 feet from the building
• Schedule pest monitoring around waste zones

4. HVAC Systems and Air Ducts

HVAC systems can spread pest activity between floors. Rodents can nest in or chew through ductwork, while insects such as termites and silverfish are drawn to condensation and organic dust buildup.

Risks include:

• -Compromised air quality
• Chewed insulation and fire hazards
• -Inconsistent temperature control due to blockages

Preventive measures:

• Seal duct joints and access panels
• Clean HVAC coils and drip pans regularly
• Inspect rooftop units for signs of nesting or droppings
• Install screens over exterior vent openings

5. Electrical and Mechanical Rooms

These areas are typically quiet, undisturbed, and warm—ideal for rodents, cockroaches, and ants. Rodents are particularly destructive, chewing through wires, causing power outages or fire risks.

Warning signs:

• Gnawed wires or insulation
• Rodent droppings near panels or baseboards
• Strange odors from equipment

Preventive measures:

• Keep areas clean and clutter-free
• Install rodent bait stations and monitoring traps
• Schedule thermal imaging inspections for unseen rodent activity

6. Raised Flooring Systems in Data Centers and Offices

Raised access floors are often found in data centers, control rooms, and IT infrastructure spaces. These voids collect dust, debris, food crumbs, and moisture. If ignored, they can become perfect hiding places for ants, spiders, silverfish, and even mice.

Issues you may face:

• Equipment damage
• Allergens and health risks
• Pest movement between floors

Preventive measures:

• Clean under raised floors at least twice a year
• Place insect monitors and traps discreetly under panels
• Keep cabling organized and elevated

7. Break Rooms, Vending Machines, and Employee Lockers

Human behavior is a major attractant. Food spills, leftover snacks, and improperly sealed containers lure pests like cockroaches, ants, rodents, and flies. Personal lockers can also harbor spoiled food or drink containers.

Common mistakes:

• Infrequent cleaning schedules
• No designated food storage policy
• Overflowing trash bins
• Preventive measures:
• Enforce a “clean desk and clean locker” policy
• Schedule daily cleaning and deep cleans weekly
• Provide sealed trash receptacles and pest-proof storage bins

8. Loading Docks, Shipping Bays, and Receiving Zones

These areas are often left open for extended periods, giving pests easy access. Incoming shipments may also carry insects or rodents from other facilities, especially via wooden pallets or corrugated cardboard.

Common entry routes:

• Gaps under roll-up doors
• Torn packaging or soft goods
• Structural cracks or unsealed wall penetrations

Preventive measures:

• Inspect all incoming deliveries before storage
• Use door sweeps, air curtains, and pest-resistant LED lighting
• Limit clutter and remove unused pallets promptly

9. Janitor Closets and Cleaning Supply Rooms

These rooms often go unchecked and may contain wet mops, leaky utility sinks, or poor drainage—making them ideal environments for mold, cockroaches, silverfish, and other moisture-seeking pests.

Key vulnerabilities:

• Infrequent access or oversight
• Unsealed chemical containers
• Mold growth due to dampness

Preventive measures:

• Elevate items off the floor using shelves or racks
• Keep the area dry and well-ventilated
• Inspect for plumbing leaks or standing water regularly

10. Landscaping, Mulch Beds, and Building Perimeters

The exterior of your building can invite pests before they ever step inside. Overgrown bushes, unmanaged mulch beds, and improper drainage near the foundation can bring in ants, termites, mosquitoes, ticks, and rodents.

Risks include:

• Insect infestations spreading indoors
• Structural damage from termites
• Mosquito breeding in stagnant water

Preventive measures:

• Maintain a vegetation-free buffer zone (18–24 inches)
• Use gravel or stone instead of mulch near foundations
• Grade soil to prevent water pooling
• Schedule quarterly exterior pest inspections

Don’t Wait Until It’s an Emergency

Pests aren’t just a nuisance—they pose serious health and safety risks to employees, customers, and your bottom line. Many infestations begin in these overlooked hotspots, quietly growing behind the scenes. By taking a proactive, integrated pest management (IPM) approach, you can:

• Identify risks before they escalate
• Protect your facility’s reputation
• Remain compliant with safety and sanitation codes
• Save money on costly reactive treatments