Can I Install a Septic Tank if my Property has a High Water Table?

Homeowners who live outside the service area of locally treated water systems rely on septic systems to protect their water sources. However, high water tables present significant challenges to the operation and maintenance of a typical septic system.

The Relationship between a Septic System and the Water Table

When water penetrates the earth, it forms two layers. The top layer is partly water and partly soil, rock, and air. The second layer is ground water. The ground water layer is so full of water there are no air pockets like in the top layer. The top plane of the ground water is called the water table. The depth of the water table varies; it can be a few feet or a few thousand feet below the surface of the earth. Changing seasons and the weather can impact the depth of the water table.

Underground septic systems typically consist of a tank and a drain field. Wastewater leaves the tank and is absorbed by the drain field. When groundwater enters a drain field, it limits the amount of disposed household water the drain field can take in. In addition, the ground water may push the disposed household water out of the system, causing waste to leach above ground, or back into the home.

Solutions to High Water Tables

As with all septic systems, it is important for homeowners to predict and plan for typical usage needs, such as laundry, bathing, toilet use and kitchen use, and ensure that an expert properly designs, installs, inspects, and maintains the system to accommodate the appropriate capacity.

Beyond these steps, homeowners with high water tables sometimes find that it is enough to simply have the septic tank commercially pumped more frequently. This addresses the volume issue, and keeps contaminated water from emerging above ground in unsafe ways, or from channeling through pipes back into the home.

Lastly, careful treatment of the water before it enters the drain field can lessen the hazards if a leaching or back-up problem occurs.

Recirculating Sand Fill (RSF)

Recirculating Sand Fill systems are an effective alternative for treating pathogens prior to the water reaching the drain field. They are considered cost effective and require little maintenance. RSF systems utilize a septic tank, a sand filter, and drain fields. Wastewater is moved from the septic tank to a recirculating tank where it moves through the sand filter up to 5 times before moving into the drain field for final treatment.

Reduce Water Use to Reduce Risk

All homeowners with septic systems can take steps to create as small and responsible an impact on their surrounding environment as possible. First, it is important to reduce water use. Consider limiting the number of times a toilet is flushed, doing laundry at a Laundromat, reducing the number of daily showers or baths, or running the dishwasher only when it is full.

Control and take care of leaks that inadvertently increase the amount of water that travels to the septic system. Routinely check toilets, showerheads, faucets, sinks as well as any other points of use and repair any leaks that are evident.

Lastly, take special care of the water that enters your system. For example, water should not flow from a basement sump pump directly into the septic system. Make sure that the area around your drain field is kept free of external water flows, such as gutters, ditches or other drains.