Pill Bug & Sowbug Identification & Control

Quick Identification

• Size: About ¼ to ½ inch long
• Color: Dark gray to slate
• Key Features: Pill bugs roll into a tight ball when disturbed (sowbugs cannot); segmented, armored body; seven pairs of legs; NOT insects — they’re crustaceans (related to shrimp and crab)
• Habitat: Moist areas under mulch, stones, flower pots, landscape timbers; enter basements and garages during rain
• Active Season: Spring through fall
• Risk Level: None — harmless moisture indicator

What You Need to Know

Pill bugs and sowbugs are among the few land-dwelling crustaceans — they’re more closely related to shrimp and lobsters than to insects. This explains their dependence on moisture: unlike insects, they breathe through gill-like structures that must stay damp. Finding them indoors is a reliable indicator of excess moisture around your foundation.

The difference between the two: pill bugs (also called roly-polies) roll into a tight armored ball when disturbed. Sowbugs cannot roll up and have two small tail-like appendages. Both feed on decaying organic matter and are completely harmless — they don’t bite, don’t damage structures, and don’t contaminate food.

Their presence indoors means moisture is finding its way into your foundation area. This could indicate poor drainage, over-mulching against the foundation, clogged gutters depositing water near the house, or grade issues directing water toward the home. Addressing the moisture solves the pill bug problem and prevents more serious moisture-related issues. Contact Sanctuary Pest Control at 815-993-3472 if you’re seeing these regularly indoors.