Slugs need cool, damp conditions because their soft bodies lose moisture quickly. Rain, wet leaves, thick mulch, shaded gardens, poor drainage, and standing water can create ideal conditions around a house. After rainfall, slugs become especially active because wet surfaces make it easier for them to move. One found indoors after heavy rain may simply have followed a damp route inside.
Where you find the slug can provide clues. One near an exterior door may have slipped underneath a gap, while one in a basement could be connected to moisture around the foundation or crawl space. Finding one in the kitchen or bathroom doesn’t automatically mean you have a leak, but it’s worth checking beneath sinks, around pipes, cabinets, windows, and floor-level openings.
