How Pests Enter Through Plumbing Systems

When people think about pest infestations, they usually imagine bugs crawling through windows or rodents sneaking in through gaps in the walls. Many don’t realize that plumbing systems can be one of the most common entry points for pests, and often the most overlooked.

At Guaranty Pest Control, we’ve seen firsthand how sneaky pests can exploit even the smallest cracks in plumbing to access homes and businesses. This post’ll explain how pests enter through plumbing, what types of pests you should watch out for, and how to protect your property from hidden infestations.

Why Plumbing Is a Common Pathway for Pests

Plumbing systems offer three things pests love:

• Moisture

• Warmth

• Shelter

Pipes run through walls, floors, and basements, often in dark, hard-to-reach spaces—making them the perfect pest highway into your home. Small gaps around pipes or poorly sealed drain systems allow pests to squeeze through and find access to food, nesting spots, and water.

Even if your home looks spotless on the outside, pests may be using your plumbing system as a direct route inside.

Common Pests That Enter Through Plumbing

🪳 Cockroaches

Cockroaches thrive in damp environments, making kitchen and bathroom plumbing an ideal hiding spot. They often enter through:

• Floor drains

• Leaky pipes

• Gaps in walls around plumbing fixtures

American and German cockroaches are particularly notorious for climbing up drains and entering from sewer systems.

🐀 Rats and Mice

Rodents can squeeze through holes the size of a coin. Sewer rats, in particular, are known for traveling through drainage pipes. If there’s a breach in your plumbing or vent system, rats can enter directly into your home through toilets or under sinks.

🐜 Ants

Many species of ants, especially moisture ants and pharaoh ants, are drawn to damp environments and standing water. They use plumbing pipes as entry points and create nests near water sources, often inside wall voids or beneath floors.

🕷️ Drain Flies and Fruit Flies

If you’ve ever noticed tiny black flies near your sink, you’re likely dealing with drain flies. These pests breed in the organic buildup inside drains, feeding on bacteria and sludge. They may not cause structural damage, but their presence is a sign of poor drain hygiene.

🐍 Snakes and Other Unusual Visitors

Although rare, there have been cases where snakes have entered homes through toilet bowls or drainage systems—especially in rural or wooded areas where plumbing connects to ground-level septic systems.

How Do Pests Get Through Plumbing?

🔧 1. Gaps Around Pipes

Improperly sealed areas where pipes enter walls, floors, or cabinets are prime entry points. Rodents, roaches, and ants can easily slip through small gaps.

🔩 2. Open or Damaged Vents

Vent stacks on your roof help regulate plumbing pressure. If these vents are uncovered or cracked, pests can crawl inside and travel through your system.

🚿 3. Broken or Dry Drain Traps

A drain trap (the U-shaped pipe under your sink) holds water to block sewer gases—and pests—from entering your home. If it dries out or breaks, it creates a direct tunnel from your plumbing to your living space.

🚽 4. Sewer Line Cracks

Cracks in your sewer line or improperly connected pipes underground can give rats or roaches access to your plumbing. They can then travel through the pipes into your home.

🧰 5. Poorly Maintained Drains

Clogged or slimy drains provide ideal breeding grounds for drain flies. If left uncleaned, they become pest hotspots and open the door to infestations.

Signs of Pest Entry Through Plumbing

• Cockroach or rodent droppings under sinks

• Scratching or squeaking sounds near plumbing at night

• Unpleasant drain odors (caused by organic buildup or pest nests)

• Flies emerging from sink or shower drains

• Chewed pipes or insulation around plumbing

• Water backing up combined with pest sightings

If you experience any of these issues, you could be dealing with a pest problem that started in your plumbing.

How to Prevent Pests from Entering Through Plumbing

✅ 1. Seal All Gaps and Cracks

Use caulk or expanding foam to seal the areas around:

• Pipes under sinks

• Plumbing where it enters walls or floors

• Utility lines in basements or crawl spaces

This simple step alone can block many common entry points.

✅ 2. Install Drain Covers and Screens

Drain covers prevent pests from climbing up pipes. Mesh screens can also be placed over vent pipes and floor drains to block entry without affecting airflow or water drainage.

✅ 3. Keep Drains Clean

Regularly clean drains using:

• Baking soda and vinegar

• Drain brushes or plumbing snakes

• Enzyme cleaners that break down organic matter

Clean drains discourage drain flies and eliminate food sources for other pests.

✅ 4. Fix Leaks Immediately

Pests are drawn to moisture, so don’t ignore dripping faucets or pipes. Water leaks also soften wood and drywall, creating ideal nesting spots for pests like ants and termites.

✅ 5. Maintain Proper Ventilation

Install exhaust fans in kitchens, bathrooms, and laundry rooms to reduce humidity levels. Dry environments are less appealing to most plumbing-related pests.

✅ 6. Schedule Regular Plumbing and Pest Inspections

Combining pest control with routine plumbing maintenance is the best way to catch small issues before they become big infestations. Professionals can spot signs that homeowners might miss.

Professional Pest Control Solutions for Plumbing-Related Infestations

If you suspect pests are entering through your pipes or drains, Guaranty Pest Control can help. Our trained technicians:

• Inspect your plumbing access points

• Identify the pests and entry areas

• Provide safe, targeted treatments

• Work with plumbers (if needed) to address structural issues

• Offer long-term prevention solutions

We take a whole-home approach, combining structural inspection, moisture control, and treatment to eliminate pests at the source.

Don’t Let Plumbing Become a Pest Highway

Your home’s plumbing should carry water, not pests. If you see bugs near your sinks, hear noises behind your walls, or notice unexplained droppings or odors, your pipes may be the culprit.

Schedule a Plumbing-Pest Inspection Today

Fill out the form below to request a professional inspection and keep pests out for good.