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Pillbugs / Sowbugs

Identification, Habits, and Control
Closeup photo of a Pillbug

About Pillbugs and Sowbugs

Order: Isopoda
Pillbugs and sowbugs are small, moisture-loving pests commonly found in damp outdoor environments. They are often seen around foundations, mulch, and landscaping and may enter homes when conditions become too wet or too dry outside. While they do not damage structures or pose health risks, their presence indoors can be a sign of excess moisture or favorable conditions around the property.

How to Identify Pillbugs and Sowbugs

Size

  • About 1/4 to 1/2 inch long

Color

  • Gray to dark gray

Identifying Characteristics

  • Oval-shaped, segmented bodies
  • Pillbugs can roll into a ball when disturbed
  • Sowbugs cannot roll up and have a flatter shape
  • Slow-moving and often found in groups

Where You’ll Find Them

  • Under mulch, rocks, and debris
  • Around foundations and landscaping
  • In damp basements or crawl spaces
  • Near entry points such as doors and windows

Behavior and Risks

Pillbugs and sowbugs feed on decaying organic matter and are most active in damp environments. They rely on moisture to survive, which is why they are commonly found outdoors in soil, mulch, and leaf litter.

Homeowners may notice them indoors during periods of heavy rain, high humidity, or when outdoor conditions force them to seek shelter. They are often found near ground-level entry points, in basements, or along foundation walls.

While they do not reproduce indoors or cause damage, large numbers entering a structure can be a nuisance. Their presence often indicates excess moisture, poor drainage, or heavy organic buildup near the home. To help prevent ongoing activity, manage moisture levels, improve drainage, and reduce debris around the foundation.