Basement Flooding: Identifying The Major Culprits

Learn the leaks – A deep dive into identifying the sources of your basement flooding nightmare

Basement flooding is unpredictable and can affect any home. While it commonly happens during heavy rains or snowmelts in spring, it can occur unexpectedly, even in dry weather. Several factors contribute to basement flooding, including seepage or flow through walls, surface water sources, and sewer backups. We have highlighted the major culprits behind basement flooding to help you mitigate the risk and keep your basement dry.

Causes of Flooding During Dry Weather

  • While most flood events occur during wet weather, it’s important to note that flooding can still happen in dry weather. Three common reasons for such occurrences include:

Failed Sanitary Lateral

  • The sanitary sewer lateral can degrade over time. Factors like tree root penetration or gradual deterioration may lead to blockages or collapse, causing a sewage backup. This results in flooding with the home’s domestic wastewater. Regular maintenance and assessment by a licensed plumber are crucial to ensure the durability of the lateral.

Blockage Due to Flushed Items

  • The improper flushing of items down the toilet can also lead to backup. It’s essential to follow guidelines and avoid flushing non-biodegradable items. Toilets are designed for human waste and toilet paper, and flushing inappropriate items can contribute to blockages.

Understanding these factors is key to preventing flooding during dry weather. Regular maintenance and responsible usage can significantly reduce the risk of sewage backups and basement flooding.

Causes of Flooding During Wet Weather

  • Flooding in wet weather is more common than during dry conditions. The primary culprit is the heavy load imposed on drainage systems by rain, ground thaw, and snowmelt. Storm and sanitary sewers, located underground, bear the burden of the additional water on the surface and below.

Surface Inflow or Overland Flooding

  • Heavy rain or rapid snowmelt can lead to the pooling of surface water around homes or in areas like driveways. In extreme weather, this water may flow into homes, especially if close to a natural stream or roadside ditch. Proper property grading is essential to minimize the risk of surface water entering homes.

Roof Drainage System Issues

  • Failure to maintain functioning eavestroughs and downspouts is a common cause of water pooling against homes. If these roof drainage systems fail or freeze during winter, water from the roof can drain alongside the house, seeping into the foundation and potentially causing basement flooding.

Foundation Drainage Failure

  • Homes typically have drainage systems to divert water away from the basement and prevent water entry. These waterproofing measures are integral to the foundation drainage system, which plays a crucial role in averting basement flooding. Here are three primary causes associated with foundation drainage failure:


  • During periods of rising water tables, water may infiltrate basements through cracks, holes, and unintended flow paths. This is often a natural aging process, and regardless of the condition of drainage materials, water can enter during heavy rains, ground thaw, or snowmelt periods. Settlement issues or improper downspout discharge can exacerbate the risk of water entering through cracks.

Sump Pump Failure

  • Homes equipped with sump pumps may require additional assistance in draining groundwater. While new homes are mandated to have sump pumps, failure due to power outages or malfunctions can lead to rising groundwater levels, causing overflow onto the basement floor.

Weeping Tile Failure

  • basement floodingOver time, the foundation drainage system, including the weeping tile, can deteriorate. Partial or complete collapse of pipes, as well as sediment blockages, can lead to weeping tile failure. When this happens, water drainage around the foundation is blocked, raising the groundwater level and potentially causing basement flooding via the sump or foundation leaks.

Leaks in sewer laterals or plumbing beneath the foundation can further complicate matters, allowing groundwater or wastewater to enter the basement through the floor drain or lowest sanitary fixture.

Whether you need help with a flooded basement or require preventive basement waterproofing services, call us at (877) 727-2259. Crack-X is a civil structures repair company operating in Maine and New Hampshire.

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