My Crawl Space Is Flooding But My Sump Pump Pit Is Dry

Placement

• A properly functioning sump pump requires a pit that is located at the lowest point in your crawl space. If your crawl space has a dirt floor, the water can erode the soil in your crawl space, creating low areas that will trap pools of water. Erosion can also deposit soil around your sump pit, creating a dam that will prevent water from flowing into it. Fill in any low spots that develop in the crawl space and clear excess dirt from around the sides of your sump pit to prevent these problems.

Drainage Lines

• The sump pump pushes water out of your crawl space through a drainage line that runs under or through your foundation walls. If the drainage line becomes clogged with dirt or roots, it can force water back into your crawl space. If you suspect a clogged drainage line, you can add water to the sump pit and check the end of the drainage line to ensure that it is working properly. If the line is clogged with debris, you can often clear it using a plumbing snake. You will have to excavate and replace drainage lines that are blocked with tree roots or that have collapsed.

Groundwater

• During periods of heavy rainfall, the height of the groundwater around your home increases. Ground in flat, low-lying areas often has a high water table that can force water into your crawl space when rainfall adds to the groundwater beneath your home. The rising level of water under your home can prevent the sump pump from emptying your crawl space even though it is working properly.

Perimeter Drainage

• Damaged gutters or underground drainage lines around your home can allow water to build up in the ground around your home. During periods of heavy rain, the pressure from excess groundwater around your home can force water through the walls of your foundation. While your gutters are pouring water into the ground around your foundation, your crawl space will continue to flood even though your sump pump is pumping the water out.

Considerations

• If your crawl space is flooded as a result of high groundwater, you can prevent moisture damage to your home using a vapor barrier installed across the floor of your crawl space. A plastic sheet installed across the floor of the crawl space will prevent moisture from reaching the insulation and wooden framing of your home.