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  • Writer's pictureEngineer Mike

How often should a foundation drain sump pump run?

Updated: Nov 21, 2023


The answer to this question is not that simple. First, it is important to understand what a foundation drain is and what it does.


 

Components of a Foundation Drain System


A typical foundation drain system consists of perforated drain pipes on the perimeter of the foundation and a sump pump. In addition, it can also include small inlets to collect water at the bottom of window wells. The pipes can be either on the interior or exterior of a foundation wall.



Labeled components of a foundation drain sump pit with pump, two drain pipes, power line, and discharge pipe.
View into the foundation drain sump pit from the top.

Water flows into the sump pit through the drain pipes and is collected in the sump pit. It is then ejected to the outside by a pump.


Note: Your home may not have a foundation drain system. It depends on the recommendations in the geotechnical (soil) report for your specific home.





The purpose of a foundation drain system is to collect water from the soil around a foundation and discharge it away from the structure. It is important to remove moisture because wet soil, which has more weight than dry soil, applies more force on a foundation wall and can cause cracks or movement. In addition, a foundation drain can be effective in preventing water from seeping into a crawlspace or under a basement floor. Moisture accumulation in a basement or crawlspace can cause problems with a slab-on-grade floor or can damage the structural components of a building.



Crossection of a basement foundation wall showing the foundation drain pipe.

 

Foundation drain sump pumps are affected by the following:

  1. Climate: Regions have different precipitation patterns and groundwater levels, such as Arizona's dryness compared to Louisiana's rain and humidity.

  2. Weather: During heavy rain, you may notice it coincides with your sump pump working more often for a short period of time. During dry weather, the sump pit may be dry.

  3. Season: It all depends on where you live. If you live in Colorado, for example, your wet season is March through May. If you live in the pacific northwest, precipitation levels are high from September through May.

  4. Drainage Problems: Proper site drainage is an important concept when considering moisture conditions of the soil in the foundation's "protective zone." The ground around a foundation needs to slope properly away from the foundation. If the slope is flat or has low spots, these features allow water to flow toward the foundation and seep into the foundation backfill.

  5. Functionality: The foundation drain system has to be properly constructed for it to function as intended and is so critical to the structure that most building departments require a specific inspection and documentation of the installation of the foundation drain. A construction field technician, typically employed by the geotechnical engineer of record, makes a trip to the construction site to document that the foundation drain was placed with the proper materials and slope and issues a letter to the Building Department to be placed in their files.



 

Common Problems of Foundation Drain Systems


Problems with the foundation drain system, which can cause structural and moisture problems, are not always, but often, due to construction defects.


 

1. Sump Pump Not Installed in Sump Pit


If required by the geotechnical (soil) report and not installed by the builder, the absence of a pump in the foundation drain sump pit is a construction defect.



Foundation drain sump pit with accumulated and flowing water but no sump pump.
From the top, view of a foundation drain sump pit with water at the bottom but no pump.

 

2. Sump Pumps on the Exterior


Although allowed in some jurisdictions, engineers do not recommend installing foundation drain sump pits on the exterior (outdoors) due to the potential for freezing and soil and debris entering the sump pit.


Foundation sump pit with pump in landscape rock on the exterior of the foundation, discharging into the grass.
Foundation drain sump pit on the outside of the foundation.

 

3. Soil and Debris in the Drain Pipe


Foundation drain pipes should be free of soil or debris to allow water to flow to the sump pit. However, if there is a small amount of material in the pipe, it does not necessarily mean the system is not functioning properly.


The cause of clogged pipes can indicate a serious problem with the foundation drain system and should be investigated by a professional engineer. Such the construction of this system is that this is a problem that will not clear itself and may need repair. Soil and debris in a foundation drain pipe are often associated with construction defects.

Mud accumulated in foundation drain system pipe.
Image from video-scoping of a foundation drain pipe showing mud accumulated in the pipe.

 


 

4. Drainage Problems


Site drainage problems can be caused by lousy grading, barriers around the foundation, or water from upstream surrounding properties. When water is allowed to collect around the foundation, especially in the foundation protective zone, it will seep into the foundation backfill material and enter the drain system. This typically manifests in excessive flow at the sump pump discharge pipe. In addition, a sump pump that runs often may be another indicator of drainage issues.


Drainage problems can be caused either by construction defects or the lack of proper maintenance. Often, homeowners themselves have installed landscape improvements that cause or make drainage problems worse. Sometimes, the problem is with the engineer's site design.


Frozen discharge in snow from a foundation drain sump pump on the side of the foundation.
In the winter, frozen discharge from a sump pump. Drainage problems in the vicinity of the foundation can cause excessive accumulation of water in a sump pit resulting in a more-than-normal amount of water discharge.

 


 


 

5. Sump Pump Discharge


The common problem is a sump pump discharge pipe that is not adequately extended away from the foundation. This can lead to a cycle of water traveling from the foundation backfill, into the drain system, out the sump pump, and back into the foundation backfill again, over and over.

A combination of having a discharge pipe that is too close to the foundation and grading problems is common.


Water stream from the discharge of a foundation drain sump pump on the exterior of the foundation.
Sump pump discharge should be extended past the 10-foot “protective zone” around a foundation.

 


 

6. Dry Sump Pit


It can be normal for sump pits to be dry at a certain time of the year. Some homes' sump pits stay dry all year round because no moisture is infiltrating the soil around the foundation, and there is no groundwater. However, if the foundation or basement floor is experiencing structural distress or moisture problems, a dry sump pit can indicate a non-functioning foundation drain system.


The lid of a foundation drain sump pit opened to show the pump and a dry bottom.
From the top, view of a dry foundation drain sump pit.

 

7. Ongoing and Excessive Pump Discharge


Continuous water seepage over surfaces, staining, mold, and algae can be caused by excessive sump pump discharge related to drainage or groundwater problems. This seepage damages pavements, sidewalks, and landscaping and may indicate a problem with the foundation. Therefore, when this situation is encountered, the cause should be investigated by a forensic engineer.


Problems with the foundation drain system, which can cause structural and moisture problems, are not always, but often, due to construction defects.


Water stains from foundation drain sump pump discharge on sidewalk in a residential neighborhood.
Visible seepage, stains, and algae growth on the surface of the sidewalk and curb-and-gutter caused by sump pump discharge.

 


 

I hope this information was helpful to you. For additional topics related to construction defects, go to SiteDamage.com.


Visit my photo collections page, which has examples of damage that can be due to construction defects.  





Mike

Engineer Mike




 

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