When you're planning to build a home on a rural plot of land, you'll need to install a septic system. In the vast majority of counties, you won't be allowed to build a home without having a septic system or acceptable alternative installed—counties want to protect the groundwater from possible pollution caused by wastewater runoff, and this effect is minimized with a functional septic system.
Finding the perfect place to put your new septic tank can sometimes be difficult. To help you find a location on your property to install your septic tank, here's what you should look for.
Away From Vehicle Traffic
When choosing a location for your septic tank installation, you'll need to choose an out-of-the-way area that's unlikely to see vehicle traffic. The weight of a vehicle can easily damage a septic tank, and it's easy for people to accidentally drive over one—even with risers to mark their location, septic tanks can be hard for drivers to spot. Your drainfield needs to be protected from vehicle traffic as well, since the small pipes in the drainfield can be crushed by vehicles driving over them.
Above the Water Table
The pipes in your septic system's drainfield need to be located a few feet above the local water table. If the pipes are submerged in water, there's no place for the effluent in your septic system to drain to. The pressure of the water in the pipes may also cause your wastewater to back up inside your home. In most locations, this doesn't present a problem, because you need to drill quite deep in order to find groundwater. However, some areas do have high water tables that affect where your drainfield can be placed.
Some areas also experience seasonal fluctuations in the water table. This can cause one of the most frustrating problems a septic tank owner can have—the septic system will work perfectly while the water table is low, and then stop working entirely once the rising water table has submerged the pipes in the drainfield.
When you're considering locations for septic tank installation, try to choose one that's elevated. Installing your septic tank and drainfield on the highest point of your property can give you the clearance that you need to prevent your drainfield pipes from being submerged by water.
You should also take a soil sample in the location where you wish to have your drainfield installed. If the location has a water table that's seasonally high, the soil sample will tell you—you'll notice a mottled water line where sediment carried by the water changes the appearance of the soil.
In an Area with Adequate Soil Drainage
Finally, the most important consideration for your septic tank location is soil quality. Your drainfield needs to be located in an area with good—but not extreme—drainage. A septic system works by trapping solid waste inside the septic tank and draining the wastewater through its outlet into the drainfield. Once the wastewater is in the drainfield, bacteria in the soil will break down any remaining solid waste. The remaining wastewater will seep harmlessly into the water table.
If the soil in your drainfield drains too quickly, then the bacteria in the soil don't have enough time to break down the solid waste before it enters the water table. If it drains too slowly, then your drainfield will fail because it becomes too saturated with water, leaving no place for the effluent from your septic tank to drain.
You can determine soil drainage by performing a percolation test. In fact, you'll nearly always need to have this test performed by the county before you can get a permit for septic tank installation in order to ensure that your wastewater doesn't pollute the local water table.
However, you can easily do this test on your own by digging holes in potential drainfield locations, filling them with water, and calculating how fast the water is absorbed into the soil. You will generally find that areas consisting entirely of gravel drain too quickly, whereas areas consisting mostly of clay will drain much too slowly to support a drainfield. You'll have to find a location on your property that has a blend of soil types in order to support proper wastewater drainage.
If you're having trouble finding a location for septic tank installation on your property, call a professional septic system installation business, such as Honest John's Septic Service Inc. Septic tank installation professionals can help you find the best location on your property for your septic system—one with excellent soil drainage that isn't near the water table.
