Your Home and the Phreatic Zone: Key Facts

By Editorial Team

Updated on November 8, 2023

Owning a house can sometimes mean adapting oneself to nature’s perils. Whether it be freeze-thaw cycles or landscape vegetation, naturally-occurring phenomena can have an impact on your house’s overall state and maintenance. 

The phreatic zone is included in the challenges caused by nature that can occur on, or more likely beneath, your property. If you want to learn more about the ins and outs and overall outcomes resulting from the phreatic zone and its impact on your house, keep reading. 

The Phreatic Zone In a Nutshell

phreatic zone

Source: Canva

The phreatic zone can be summed up in two parts: the unsaturated zone, which represents the ground within which water flows, and the saturated zone, which is an underground water reserve that can be found, depending on the landscape, at various levels underground. 

The above-mentioned water reserves are a result of rainwater that seeps into the ground and ends up in the earth. A house can be built atop the unsaturated (ground) part of the phreatic zone. Quebec’s phreatic zone amounts to 25% of our drinking water supply!

To learn more about the phreatic zone, check out this article! (French only)

Keep an Eye On Your House’s Phreatic Zone!

phreatic zone

Source: Canva

As previously mentioned, the phreatic zone can be found at differing levels beneath your home’s foundation. And, water coming from the phreatic zone can, at times, leak into your basement if the former is too close or above your foundation’s level. 

Some warning signs can help you determine whether there’s a phreatic zone near your house. The most common sign is water seeping into the basement. Water from the phreatic zone naturally flows toward the water cavity via soil and should your home’s foundation be “in the way,” and your foundation isn’t properly drained, it’ll inevitably lead to water leaks. In some cases, water from the phreatic zone can rise above the ground and flood your basement. 

If you start noticing humidity problems or a buildup of water in your basement, it’s about time to reconsider your drainage options. A French drain will drain any water flowing toward your foundation and redirect it toward the nearest rainwater sewer. 

That said, merging the possibility of a too-high phreatic zone with spring rainfalls, a French drain won’t suffice. In such a case, you should really consider relieving the French drain by installing a sump pump. 

Water Buildup: To Pump or Not

phreatic zone

Source: Canva

A too-high phreatic zone can very well put pressure on your current drainage installations, on top of other water sources on your property resulting from, for example, melting snow. 

The sump pit will take over once the French drain becomes insufficient in terms of draining water: the French drain will thus redirect the excess water toward the sump, which is basically a water pit.

The pump fitted to the sump pit will draw the excess water toward the rainwater sewer via a pipe that was installed beforehand. Prior to installing any kind of pump to your sump pit, you have to be aware of its dimensions. If your sump pit is over 18 inches wide, it could easily fit a submersible pump with a float switch. Once the water in the sump pit raises the float to a predefined level, the pump will be activated and push the water toward a rainwater sewer. 

If it’s less than 18 inches wide, a pedestal sump pump is required. This model is designed for narrower sumps and is non-submergible. It also works with a float switch that powers the pump once the water hits a certain level. 

A sump pump can be directly connected to your household’s electrical system or battery-powered in cases where it’s a backup sump pump. In the event of heavy rains causing a power outage, a battery-powered sump pump allows you to continue draining the water for a couple of hours following the power outage. 

Check out our article 6 Ways to Deal with Flooding if you want to be well-versed when faced with any kind of situation!

In Conclusion

The phreatic zone consists of two sections: the unsaturated section, which embodies the ground within which water flows toward the saturated section, which in turn refers to the water cavity beneath ground level.

If you experience water leaks in your basement, it's likely that you're property is near or on top of a phreatic zone. In such a case, make sure your drainage systems are working properly!

Choosing to use a sump pump designed to work cohesively according to the latter is super important, and do make sure to choose a pump that’s suitable to your situation and to the land on which your house stands. 

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