Rule out these causes before you buy a waterproofing system
A plumber can test several of these in one visit. Each one has a different fix.
- A leaking supply or drain pipe. Water on the floor next to a wall may come from a pipe, not the ground. See leak detection.
- Condensation on cold pipes and walls. Warm, humid air on cold surfaces drips and pools. Insulation and dehumidifying help.
- A clogged or failing drain. A floor drain that backs up shows water that is not groundwater. See drain cleaning.
- A failed sump pump. The pit fills, and the water has nowhere to go. See sump pump repair.
- Surface drainage. Downspouts that end at the foundation and soil that slopes toward the house send water to the basement.
- A water heater or washing machine leak. Appliances leak slowly and the water spreads across the floor.
What fixes what
Waterproofing is a set of tools. This table shows which trade handles which cause.
| Cause | Typical fix | Who usually does it |
|---|---|---|
| Plumbing leak | Repair the pipe or fitting | Plumber |
| Groundwater rising through the floor | Interior drain and sump pump | Plumber or waterproofing contractor |
| Water through the wall or at the footing | Exterior excavation, membrane, drainage | Excavation or waterproofing contractor |
| Gutters and grading | Downspout extension, regrade | Landscaper, roofer or homeowner |
| Cracks in poured concrete | Epoxy or polyurethane injection | Foundation or waterproofing contractor |
| Condensation | Insulation and dehumidification | Homeowner, HVAC or insulation contractor |
Interior drains and sump pumps
An interior drain system sits along the inside of the footing under the slab and collects water before it reaches the floor. It drains to a sump pit where a pump sends it outside. This is the plumbing part of waterproofing, and a plumber can design the pit, the drain connections and the discharge.
The discharge matters in Guilford, because the town has no municipal sewer and its health department advises keeping sump pumps and footing drains away from the septic system. A system that dumps water onto the leach field can fail the septic system while saving the basement.
Why groundwater is a Guilford question
Guilford is a coastal town with tidal wetlands along its rivers and creeks, and its plan of conservation and development warns that rising water tables in coastal areas can make septic systems fail. NOAA's climate normals for 1991 to 2020 show about 42 inches of annual precipitation at the coastal New Haven Tweed station and about 50 inches at inland Mount Carmel. Wet years raise the water table, and a basement below the water table lets water in.
If your basement has taken water in a storm, ask whether the property is in a FEMA flood zone. Guilford's Engineering Department says work in the Special Flood Hazard Area can require a Flood Hazard Permit, and a plumber can describe which plumbing work is involved.
Paint, sealers and what they cannot do
Waterproofing paint and sealers coat the wall surface. They can help with minor dampness, but they do not stop water pushing through under pressure, and they can peel when water gets behind them. Treat them as a cosmetic layer, not a drainage system. If there is liquid water, it needs somewhere to go.
Where our work ends
We handle pumps, interior drains, drain lines, supply leaks and the plumbing connections of a waterproofing job. We do not excavate foundations or apply exterior membranes. When the cause is outside the wall, we say so, and you can take that finding to the contractor you choose, which saves you from paying for a plumbing fix that will not work.
What affects the price of the plumbing side of waterproofing
Costs depend on the cause.
- The cause.A repaired pipe costs far less than an interior drain with a sump pump.
- Length of interior drain.More perimeter means more concrete to cut and patch.
- Pump size and backup.Higher flow and battery backups add equipment.
- Discharge route.A long run and a septic-safe outlet add work.
- Finished space.Drywall and flooring must be moved or replaced.
Insurance rarely covers seepage and groundwater. It may cover damage from a sudden plumbing failure. Find out before you file.
Wet basement and not sure why?
Call the line, say where the water shows up and whether it appears during rain. If water is rising right now, ask for emergency service and the call is handled that way.
Questions we hear on calls
A plumber handles drains, sump pumps and pipe leaks. Exterior excavation and membranes belong to waterproofing and excavation contractors. We say which applies after a visit.
Water that appears only during rain suggests groundwater. A steady supply of water in dry weather suggests a pipe. A plumber can run tests.
For minor dampness, sometimes. It does not stop water that pushes through under pressure.
It handles water that reaches the pit. If water enters through walls, other measures may be needed.
Not usually, but a flooding basement during a storm is. Call the 24/7 line and ask for emergency service.
Sources for the local details on this page
The local facts above come from the Guilford plan of conservation and development, Guilford Engineering Department flood hazard permit page and town's septic system brochure. Rules and figures can change, so check with the town or state office before you rely on them for a permit or a purchase.