Start with where the water comes from
Water enters basements from the ground, through floor cracks, through the joint where the wall meets the slab, or through window wells. It can also come from inside, such as a plumbing leak, a failed water heater or condensation on cold pipes. Fixing the wrong one wastes money.
The plumber begins with a walk-through. A plumbing leak is ruled out with the meter test on our leak detection page. If water follows rain or snowmelt, drainage is the issue. Condensation shows on cold surfaces in humid weather and calls for ventilation, not a pump.
Waterproofing options compared
Each approach deals with water differently.
| Approach | What it does | Best for |
|---|---|---|
| Grading and gutters | Moves roof and surface water away from the foundation | First step for most wet cellars |
| Interior drain channel | Collects water at the wall-floor joint and sends it to a pit | Seepage at the floor edge |
| Sump pit and pump | Removes collected water from the cellar | High water tables and drains |
| Crack and wall sealing | Seals specific entry points | Isolated cracks, with limits |
| Exterior excavation and membrane | Seals the outside of the wall | Major wall failures, at higher cost |
Wet cellar after every storm?
Call for a walk-through that finds the cause before a fix is proposed.
Cheap fixes to try first
Check that gutters are clear and that downspouts discharge well away from the house. Grade the soil so it slopes away from the foundation. Seal window wells and keep them clear. These steps cost little and often reduce water enough that a larger system is not needed.
If water still arrives after heavy rain, an interior drain and a sump pump handle what drainage cannot. Our sump pump installation and repair page explains pit and pump choices, including backup power.
Soil, water table and local patterns
Rockingham County has seen flood and storm declarations in past years, and the regional planning commission has recorded events in 2006, 2007, 2008, 2010 and 2011. Those are county-level records, not specific to a Derry street. They show why a basement near a pond, brook or low spot in Derry, Windham, Hampstead or Chester may face water more often than one on a ridge.
Homes near Beaver Lake or other water bodies tend to have higher groundwater. A spring thaw can raise it for weeks. A plumber can tell you which sign points to groundwater and which to a leak, and the pump system is sized to the risk.
What a waterproofing visit includes
The visit is about finding the cause before selling a system.
- Inspect inside and out. The plumber checks walls, floor, gutters, grading and window wells.
- Test for plumbing leaks. A meter test and visual check rule out supply and drain leaks.
- Recommend the least invasive fix. The plumber lists options from simple to major.
- Quote and schedule. You get a clear price before work starts, and the work is scheduled around dry weather where possible.
Questions to ask a waterproofing contractor
Basement work is expensive, so ask these.
- Where is the water coming from, and how do you know?
- What cheaper options did you consider first?
- Where will the pump discharge?
- What happens during a power outage?
- What warranty applies, and what voids it?
Basement Waterproofing questions in Derry
Run the meter test: turn off all water and watch the meter for fifteen minutes. If it moves, a leak is likely. If water follows rain, it is probably groundwater or drainage.
If water collects in the cellar after storms or during the spring thaw, a pit and pump can help. The plumber assesses the volume and the drain to decide.
It manages liquid water that enters at the floor and wall. Humidity and condensation are different problems and may need ventilation or a dehumidifier.
Planned waterproofing is not. If your cellar is flooding now, call the 24/7 line for sump pump emergency help.
Policies differ, and many exclude groundwater seepage. Ask your insurer, and keep photos if a pipe burst caused the water.
References: Rockingham Planning Commission regional plan for county flood history. Derry code enforcement, 603-432-6148, for sump discharge and permit questions.
Keep the cellar dry
Call to schedule a basement waterproofing assessment in Derry.