


Septic Systems
We specialize in the design and installation of onsite sewage disposal systems, commonly called "septic systems". These critical pieces of your home or building's infrastructure are designed to safely treat raw sewage, protecting the ground and surface water from contamination. It's important to properly install and maintain them, and you can learn something about that here! Below you will find some useful pictures and documents.
Test Holes

Usually the first step in the design of your septic system is to dig test holes to determine the nature of the soil on the lot. Remember, in areas not served by a public sewer system, the septic permit is the very first step in obtaining a building permit, so it's good to get this started right away. The local Health District will evaluate the test holes, and work with us to design the best system for your situation. The picture shows ground water at the bottom of the hole, but often it's rock, rather than water, that limits the depth.
Septic Components

The septic system starts with the building sewer line that exits the building with a cleanout near the wall. This drains to the septic tank, where solids drop out and are slowly digested by bacteria in the tank. Liquid effluent flows out the far end of the tank, through a baffle designed to block solids, and out to the drainfield. At the drainfield, the effluent percolates through the stone, sand, or other drainfield media, percolating into the soil, or drawn up through the roots of covering vegetation. It is important to keep the drainfield shallow enough that it can "breathe", so that the soil microbes can properly treat the effluent. Generally speaking, 4' of soil below the drainfield is required to adequately treat the effluent, before it encounters rock or groundwater.
Building Sewer

The building sewer will usually be a 4" PVC pipe, carefully graded to allow liquids and solids to drain. It will have one or more cleanouts installed on it, that allow cleaning of the line in case of clogs. Ideally these cleanouts should be installed above grade to facilitate easy locating and service access.
Septic Tank

The septic tank is the primary treatment tool in the system. It will be constructed of concrete or plastic, depending on the site. It is designed to allow all of the solids to settle out, where most of them are slowly digested, but not all. The "not all" is why your tank will need to be pumped out occasionally, to remove the built-up solids that cannot be digested. The tank is where nearly all regular maintenance of your system takes place, which is why we install risers to grade over all the critical parts. Not only does this facilitate easy service access, it can serve as a reminder that what's under that green lid might need some occasional TLC! Once in regular use, the tank will always appear to be full to the bottom of the outlet, but NEVER above the top of the outlet.
Effluent distribution

Once the liquid effluent leaves the tank, it will be distributed out to the drainfield. Equal distribution is important, and is accomplished with a level pipe tee, or a multiple-port distribution box, as shown above.
Drainfield

The drainfield is the final treatment component. It is designed primarily to evenly distribute the effluent over the receiving soil, and to allow oxygen to keep the soil microbes breathing well! Some designs of drainfield with a sand component pre-treat the effluent before it reaches the soil, reducing the amount of soil needed below the drainfield before rock or groundwater. Often the drainfield will have vent pipe sticking above ground, which is critical for the proper health of the system. If you don't like the look of it, talk to us about the options we might have to hide it.
Why?

Properly designed and maintained septic systems keep us from harmful pathogens, and protect our water. Idaho is well known for it's fantastic water quality, and we hope you will join us in doing our part to protect it!