Symptoms
- Water droplets or dripping from a cold water pipe
- Damp insulation or a small puddle under a pipe
- Worse in humid weather or in basements/crawl spaces
Likely causes
- CommonCold water pipe passing through humid airThe temperature difference between the pipe and the surrounding air causes moisture to condense on the pipe's surface.
- CommonLack of pipe insulationUninsulated cold pipes condense more readily than insulated ones.
- PossibleHigh ambient humidity in the spaceA damp basement or crawl space makes condensation worse on any cold surface, including pipes.
What to do
- Confirm the dripping is condensation and not a pinhole leak by drying the pipe fully and watching closely to see if moisture reforms without any pressure change.
- Wrap the cold pipe with foam pipe insulation sleeves, sized to fit snugly.
- Reduce ambient humidity in the space with a dehumidifier, especially in basements and crawl spaces.
- Improve ventilation in the area if practical, since stagnant humid air condenses more than circulating air.
- Check for and dry any wood or material that's been getting wet from the dripping to prevent mold or rot.
- Insulate other exposed cold pipes nearby while you're at it, since they likely have the same issue.
- Call a plumber if you're unsure whether it's condensation or an actual leak, since a small ongoing leak needs different action.
Tools and parts
- Pipe insulation sleeves
- Utility knife
- Tape
Foam pipe insulationSearch: “foam pipe insulation sleeve”
When to call a pro
Call a plumber if you can't tell whether it's condensation or an actual pipe leak.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.