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Moisture

Moisture Control in Bathrooms and Under Sinks

A dripping faucet or a floor that never quite dries is all cockroaches need to move in. Excess moisture attracts cockroaches, ants, and mold; bathrooms and areas under the sink have pipes, drains, and leaks that sometimes go unnoticed. In Costa Rica's humid climate, fumigation and pest control against cockroaches work better when you lower the moisture in those areas first. Here's what to check and what to do. Combine this with eliminating moisture sources, prevention in the kitchen and bathroom, and cleaning; if there's already an infestation, get professional control.

Drying a bathroom and fixing leaks to prevent moisture
Drying surfaces and fixing leaks in the bathroom and under the sink reduces moisture.
Goal

Keep ambient humidity below 50% (less favorable for cockroaches). In very humid areas, a dehumidifier helps.

What to check (and what to do)

  • Leaks: check faucets, pipe joints, and hoses under the sink. A steady drip is enough to attract cockroaches; repair or replace washers.
  • Dry thoroughly: after showering or washing up, dry the floor, sink, and splashed areas. Don't leave puddles or damp towels piled up; hang towels so they can air out.
  • Drains: make sure they're not clogged or leaking underneath. Use covers or grates that don't let insects through; at night you can plug the drain if you've already seen cockroaches.
  • Ventilation: open windows or use an exhaust fan in bathrooms to reduce condensation; in the kitchen, ventilate while cooking. Concentrated steam raises humidity a lot.
  • Dehumidifier: in very humid areas, keeping humidity below 50% makes the environment less favorable for cockroaches. Place it near the bathroom or kitchen if possible.
Gray silverfish (Ctenolepisma longicaudata), a pest associated with moisture in bathrooms
Silverfish are a common pest in bathrooms and other humid areas of the home. Source: Wikimedia Commons (CC BY-SA 4.0).

A quick trick

Not sure if there's hidden moisture under the sink or behind the toilet? Place a paper towel or napkin at the pipe joints and on the floor below; if it gets damp or darkens within a few hours, there's a leak or condensation. That way you can find the spot without waiting to see stains or cockroaches.

Pest control spraying on a bathroom floor next to the drain
Application on the bathroom floor next to the drain: the most critical moisture point in the house.
When to ask for help

Less moisture reinforces cleaning and sealing food and trash. If you still have a lot of cockroaches, professional control can treat hidden refuges.

Cockroaches from moisture?

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EcoPlagas Technical Team

Pest control specialists · EcoPlagas

Content prepared by the EcoPlagas technical team (Ecofumigadora Hermanos Paniagua S.R.L.), a pest control company authorized by the Ministry of Health, with a registered chemical regent and trained technicians. Over 10,000 customers served from 12 locations, green-label products. Learn more about us.