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Site Drainage Practices to Minimize Localized Flooding

Description

Localized flooding or pooling around the foundation of a house can occur during heavy rains if the site is not designed for adequate drainage (Figure 1). This can lead to many homeowner headaches – wet, muddy, or icy conditions along entryways to the home; water entry into the home; and mold, mildew, and rot in building components. Standing water and constantly damp conditions can also attract insects and rodents.

Poor drainage conditions can enable water to pool around the home.
Figure 1. Poor drainage conditions can enable water to pool around the home (Source: Steve Easley & Associates).

 

There are several steps that builders can take to reduce the likelihood of standing water and localized flooding around the home during rainy conditions. These actions are described in the following guides:

Gutters and Downspouts

Final Grade Slopes Away from Foundation

Patio Slabs, Porch Slabs, Walkways, and Driveways Slope Away from House

Swales, Drains, and Site Grading for Stormwater Control

Footing Drain Pipe

Drain or Sump Pump Installed in Basements or Crawlspaces

Capillary Break Beneath Slab - Polyethylene Sheeting or Rigid Insulation

Damp-Proof Exterior Surface of Below-Grade Walls

 

The above guides are helpful for new and existing homes. Here is additional guidance specific to existing homes with basements and crawlspaces that are experiencing water intrusion issues.

Water Management of Existing Basement Floor

Water Management of Existing Crawlspace Floor

More Info

Contributors to this Guide

The following authors and organizations contributed to the content in this Guide.

Pacific Northwest National Laboratory

Last Updated

Disclaimer

This content is a work created with funding provided by the United States Department of Energy under Contract no DE-AC05-076RL01830 for the operation of Pacific Northwest National Laboratory. The information and guidance provided by Pacific Northwest National Laboratory (PNNL) in the content are intended solely for educational purposes only and do not constitute formal training or certification. It is provided with the explicit understanding that neither the United States Government nor the United States Department of Energy, nor the Contractor, nor any or their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Viewers assumes full responsibility for all actions that they may take from information provided in this content including ensuring the safety, code compliance, and proper functionality of any products they choose to install. Installation and use of such products should be performed in accordance with local regulations and manufacturer instructions.