How to Get Rid of Sowbugs
At a glance
- Difficulty: Beginner
- Time: A weekend to address moisture and foundation debris; ongoing sweeping of strays
- Cost: Low — a dehumidifier, caulk, and a rake
- Success: High once the moisture source is fixed — sowbugs can't establish indoors without dampness
Can you DIY Sowbug?
The verdict on Sowbug DIY
A beginner-friendly DIY — fix the dampness and sowbugs leave on their own.
Sowbugs (genera Oniscus, Porcellio) are terrestrial isopods — land crustaceans, not insects. Unlike their close relative the pillbug, sowbugs cannot roll into a ball and have two short tail-like appendages (uropods) visible at the rear. They're harmless decomposers that wander indoors from damp areas and die within a day or two without moisture. There's no infestation to eliminate with pesticide; drying out and blocking the moisture and harborage that drew them in is the actual fix.
The 5 DIY methods — honestly graded
Every approach graded for this species, in IPM order — prevention first, chemistry late. Pick a method to see how it works, the steps, and what it actually takes.
Prevention / Exclusion
Works wellMoisture and harborage reduction is the real fix — the dominant lever for this species, not pesticide.
Sowbugs can only survive where humidity keeps their gill-like respiratory structures moist. Removing damp harborage and sealing entry points removes both their habitat and their route indoors.
Best for: Solving the root cause, not just the symptom
Cut the moisture
Ventilate crawl spaces and basements, fix leaking pipes and gutters, and run a dehumidifier in persistently damp areas.
TipTarget basement/crawl-space relative humidity below roughly 50%.Move harborage off the foundation
Pull mulch, debris, and firewood at least several inches away from the foundation, and seal foundation cracks and gaps.
Tools & materials
Why DIY falls short here
Not scare tactics — the specific, proportionate reasons a home attempt can stall for this species.
Moisture ignored
Sprays or repeated sweeping fail to stop the problem while the moisture source that drew sowbugs in the first place remains unaddressed.
Large outdoor population unrecognized
Many sowbugs indoors signals a large, healthy damp population living just outside your walls — indoor cleanup alone won't shrink that source.
Foundation mulch bridges
Mulch or debris piled against the house acts as a bridge that funnels sowbugs directly to foundation gaps, undoing sealing efforts.
How risky is it, really?
An honest read — most nuisance species are genuinely low risk, and we say so.
Sowbugs are harmless — they don't bite, sting, spread disease, or damage the structure. Indoors, they're best understood as a moisture indicator, not a threat to your health or home.
- Bite, sting, or disease transmissionRare
Not documented — sowbugs have no mouthparts capable of biting people and carry no known disease risk
UC IPM
- Structural or property damageRare
They feed on decaying organic matter, not sound wood or building materials
Missouri Department of Conservation
- Large indoor numbers signaling a moisture problemOccasional
A practical flag worth investigating (leaks, poor drainage, crawl-space humidity), even though the sowbugs themselves are harmless
UC IPM
Can't Find the Moisture Source?
A hidden leak or drainage problem can be hard to track down on your own. Anchor Pest Services offers a full moisture and exclusion assessment across southern and central New Hampshire. Family-owned since 2017, NH license #782664.
Call a pro when…
- Sowbugs persist after your own moisture and exclusion fixes
- You suspect a hidden leak or drainage problem you can't locate
- You want a full building-envelope moisture and exclusion assessment
General Pest Control
You rarely need a pro for sowbugs — this is a moisture-and-debris job. The exception is a persistent, hard-to-locate moisture source (a hidden leak, poor grading, or crawl-space humidity you can't resolve yourself).
Keep them out
- Keep basement/crawl-space humidity below roughly 50%
- Move mulch, debris, and firewood away from the foundation
- Fix leaks and improve drainage away from the house
Sowbugs in New Hampshire
Sowbugs are closely related to woodlice and pillbugs, and common names for these terrestrial isopods overlap regionally. In New Hampshire's humid basements and crawl spaces, sowbugs are most active in the wetter shoulder seasons — spring and fall — when outdoor moisture is high, wandering in from damp mulch beds and foundation soil.
Peak season
Spring and fall, during high-moisture periods
First-frost anchor
Manchester first hard frost ~Oct 19 (50%) / Oct 29 (80%), NOAA 1991–2020
Make sure it's a Sowbug
Two quick detours worth taking — confirm the ID, then learn what drew it in so it doesn't come back.
Frequently asked
Sources & further reading(2)
- [1]UC Statewide IPM Program — Pillbugs and Sowbugs
Species identification, harmless status, moisture dependency, control recommendations
extensionverified 2026-07-13 - [2]Missouri Department of Conservation — Pillbugs and Sowbugs (Land Isopods)
Species distinction, decomposer role
govverified 2026-07-13
Written & reviewed by
VerifiedDaniel Brady
NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)
Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.
Last updated July 2026
Other species you can tackle
Same category — the dot shows each one's DIY verdict at a glance (green = friendly, amber = doable with care, red = call a pro).
Professional Pest Control
Can't Find the Moisture Source?
A hidden leak or drainage problem can be hard to track down on your own. Anchor Pest Services offers a full moisture and exclusion assessment across southern and central New Hampshire. Family-owned since 2017, NH license #782664.
- Moisture-source diagnosis
- NH-licensed applicators (#782664)
- Free inspection — same-day service across southern NH
NH License #782664 · No obligation · We answer in person