What Is a High Water Table?

High water tables can cause significant issues for homeowners, even with advanced construction techniques. When the water table is just above the crawl space or basement floor, groundwater may seep into the foundation.

This leads to water damage and serious structural problems over time, especially in areas with dense, absorbent soil. In this guide, we’ll explain what high water tables are and how to manage them.

High Water Tables Explained

Diagram of high water table leaking into basement.

A high water table occurs when the groundwater is close to the surface, sometimes just above the crawl space or basement floor. This usually happens after heavy rain or when water from higher elevations (like on a hill or mountain) drains into the soil around your home.

The water table fluctuates depending on various factors, such as rainfall, seasonal changes, and human activities like irrigation or construction. In areas with poor drainage, high water tables can cause serious problems.

Types of High Water Tables

There are two main types of high water tables:

Perched Water Tables: This type forms when pockets within the earth’s crust trap groundwater, making it unable to seep further down. This can happen even on higher ground and typically involves bedrock or dense clay.
Seasonal High Water Tables: These occur during certain times of the year, such as late winter and early spring, due to melting snow and increased rainfall. The excess water pushes the water table up, which can cause flooding in your yard.

How a High Water Table Can Affect Your Home

A high water table is more than just an inconvenience; it can be a serious threat to your home’s stability and safety. Here are three major ways a high water table can cause damage:

Foundation Shift: Groundwater can create hydrostatic pressure, where water in the soil pushes against your foundation and causes cracks. This can lead to serious structural damage and foundation settlement.
Flooding: A high water table can lead to flooding in your basement or crawl space, especially during heavy rains or rapid snowmelt. This can cause damage such as wood rot and increase the risk of mold growth.
Humidity Issues: High water tables can actually lead to high humidity levels in your home. This causes high energy bills and structural damage, especially if you have a lot of wood in your basement or crawl space.

How to Measure the Water Table on Your Property?

To measure the water table, you can use tape to measure the water level in a shallow well. If you don’t have a well, acoustic or electric probes can be used. However, in most cases, it’s best to call a professional for an accurate assessment.

How Professionals Measure the Water Table

Professionals have specialized tools and techniques to measure the water table accurately. Here are some methods they use:

Observation Wells: Professionals may install observation wells or piezometers that go into the ground to monitor groundwater levels. These wells provide direct measurements of the water table.
Soil Moisture Sensors: These sensors go in the ground to measure soil moisture content at different depths. They can provide valuable data about the water table’s location and movement.
Geophysical Methods: Techniques like electrical resistivity and ground-penetrating radar (GPR) can be used to create detailed images of the subsurface, helping to identify the water table and other underground features.
Hydraulic Tests: Professionals may conduct tests like pumping tests, where water is pumped from a well to observe changes in the water table. These tests help determine the aquifer’s properties and the water table’s behavior.

What Can You Do About a High Water Table?

If you have a high water table, here are some solutions professionals can help you install:

Yard Drainage: Installing surface and subsurface drainage systems can channel water away from your foundation, preventing storm water from weakening your home’s structure.
Underground Pipes: Also known as weeping tiles, these pipes are laid in a gravel bed below the soil grade to capture and redirect water away from your home.
Swales: These are shallow channels that direct excess water to a municipal drain, placed to suit the grading of your yard.
Waterproofing: This involves using sump pumps and interior drains to keep water out of your basement or crawl space.

Get a Free Home Inspection With AFS

AFS inspector posing with leveling tool.

If you’re having trouble with a high water table, consider contacting AFS Foundation Repair & Waterproofing Specialists. Our team will provide you with a free inspection to determine if your water table is a risk to your home, and recommend the best waterproofing solutions. You’ll be able to enjoy your home safely once again.

Schedule Free Inspection

High Water Table FAQs

How can I tell if I have a high water table on my property?

Signs of a high water table include persistent wet spots in your yard, water seeping into your basement or crawl space, and foundation cracks. A professional assessment can provide an accurate measurement and confirmation.

What is hydrostatic pressure, and why is it bad for my home?

Hydrostatic pressure is the force that groundwater exerts against your foundation. This pressure can cause cracks in your foundation and walls, allowing water to seep into your basement or crawl space, which can lead to serious damage.

What is the best way to keep my basement dry if I have a high water table?

The best way to keep your basement dry is to waterproof it. This can include installing sump pumps, interior drains, and sealing cracks in the walls. A professional can help you choose the best solution for your home.

Resources

5 Benefits of Waterproofing Basement Walls

Wet basement walls can be fixed with a vapor barrier, learn about the benefits here!

Hydrostatic Pressure Explained: 4 Tips to Stop It

Hydrostatic pressure can cause big problems for your home, especially if you have a basement.

Why Every Basement Needs a Sump Pit

The sump pit is essential for keeping your basement in good condition and safe.

Ted Dryce

Content Writer

Ted is an SEO Content Writer who has been with Groundworks since 2021. He’s covered home repair topics ranging from crawl space encapsulation to regional soil conditions. When he’s not working, Ted is performing improv comedy and working on his own creative projects.