All About Groundwater

What is Groundwater? 

Groundwater is water that is present below the surface of the earth. It can be found underground in cracks and spaces in the soil, moving through formations in the soil and rock called aquifers. The top of this “groundwater zone” is known as the water table. During periods of high precipitation, the water table will gradually rise as the water seeps into the ground. In the summer, the water table typically falls as plants absorb water into their roots before the water can make its way down to the water table.

Groundwater can be clear and look clean, but it can also contain minerals and leave discoloration on pavement over time. The use of irrigation systems to water lawns, gardens and other landscapes increases the height of the water table and can sometimes cause pooling and unexpected water appearances in areas that had never previously been affected.

When left unmanaged, groundwater can have major effects on home foundations, leading to cracks in the foundation or even a wet basement. Soil around a house’s foundation can also shrink and grow over time as a result of groundwater levels causing water access or increased pressure on the foundation.

Protection of Groundwater Quality

The quality of groundwater is important to protect! This is because the water may eventually flow into rivers and lakes, which will impact wildlife and the environment. Here are a few tips to protect groundwater quality:

• Use natural alternatives on your lawn and garden when you can!
• Properly dispose of motor oil, unused chemicals or medications properly, never dump them down the drain or on the ground.
• Safely store chemicals indoors or in covered areas to prevent runoff.
• If you have a septic system, ensure that it is regularly maintained and inspected.

What You Can Do

To help manage groundwater on your property and mitigate potential impacts, we recommend you:

• Check for leaks and overwatering. Watering three days or less per week will allow your soil to dry out in between watering days. Check out the Thornton Watering Guide for more recommendations on when and how often to irrigate.
• Check the foundation of your home. The ground surface should be sloped away from the foundation for proper drainage.
• Talk to neighbors about seeing similar conditions of groundwater.
• Place rain gutter downspout diverters and sump pump discharge pipes in a position to allow water to exit a safe distance away from the foundation and drain away from structures. It should drain out into the city curb and gutter.
• Make sure your drain pipes, gutters, and downspouts are clear of all debris.
• If you have drainage problems on your property, consider installing a French drain. This is a trench filled with a perforated pipe and gravel, which allows water to drain naturally from your yard. If you prefer to DIY, you can purchase the supplies at a local hardware store and install a French drain yourself.