1. A plumbing leak
If the water appears even in dry weather and your water meter moves with everything off, a pipe is probably leaking. Check around the water heater, washing machine, supply lines and drain stacks. See water leak detection.
2. Groundwater seepage
Water that seeps through walls or up through the floor after rain, often at the base of walls or along cracks, is usually groundwater. Efflorescence, the white mineral deposit on masonry, is a sign water has passed through. The Village lists wall and floor sealing, perimeter drain tile and a sump pump as ways to address it.
3. Surface water
Water that enters at windows, window wells and the tops of walls usually comes from poor grading, clogged gutters or disconnected downspouts. Clear gutters, extend downspouts and check window wells.
4. Sewer backup
If water comes up through floor drains or toilets, especially during heavy rain, it is sewer backup. The Village explains that when street sewers fill, house sewers that also carry downspouts and fixtures drain poorly and can back up, and it identifies the northeast quadrant as especially affected. Backflow prevention or an overhead sewer addresses this; see flood detection and prevention and sewer and drain leak detection.
How to tell which one you have
- Note whether water appears only after rain.
- Do a meter test with all water off.
- Check where the water appears first: pipe, wall, floor or drain.
- Look at the color and smell: sewage is distinct.
- If still unsure, have a professional map moisture and test the plumbing.
Next steps
Fix the right problem. Waterproofing will not fix a pipe leak and a pipe repair will not stop a backup. See basement and foundation leak detection and moisture mapping.
