First time buyers - The house has a septic. What’s that?

Many first-time buyers have always lived in an environment where sewers were available or perhaps they just didn't think about where the waste water from their parents’ home went. Now that there are buyers and looking in the suburbs they will often hit homes that are advertised as being on well and septic system.  In the last post we covered having a well as a source of water for a house. In this post we’ll look at where that water is going to end up going.

When you flush the toilet or turn on the shower the water and everything with it goes somewhere. In the city there are sewers to carry the waste water away to a treatment plant somewhere, where it is treated to remove the waste solids and purify the water enough to be released back into a river or lake. In suburban settings you don’t have the sewers to carry the water away, so you have to have your own little treatment facility to deal with your waste water. That facility is called a septic system.

Just like for the well as a system to supply your water; there is really nothing to be afraid of with having a septic system to deal with your waste either. But, just like for the well; there are things that you should be aware of and things that may need attention over time.

It its most simplistic level the septic system consists of a tank with two chambers that is connected to the waste plumbing in your house. The waste water flows into that tank from the house. On the other side of the tank are pipes leading out to what is called the drain field or leaching field. Most of those pipes have holes in them, so that the water in them can flow out into the soil. Those pipes are deep enough to avoid freezing in winter.

So how does this all work? Well, as the waste water and solids flow into the tank, some things float to the surface and some sink to the bottom of the tank. Think of this tank as a big digester for the solids that flow into it. Bacteria in the tank break down or digest most of that material. Some of the stuff that floats to the top gets digested too, but some is made up of things that the bacteria can’t eat. Over time that layer builds up, as may the sludge at the bottom, so it is recommended that the tank be pumped out every 3-5 years. The tank is engineered such that only liquids are supposed to flow into leach field.

In normal operation as the tank fills with liquid eventually it will reach a level within the tank where the leach field pipes exit the tank. The liquid runs out into those pipes and from them into the ground itself where it percolates downward, pulled down by gravity towards the water table. During the process of that percolation the liquid is purified again by bacteria that live in the soil. Eventually that water joins the ground water aquifer at some level underground. Because that aquifer may be the same one that your well is tapping into the two are required to be at least 100’ away from each other. Keep that in mind also when you dispose of hazardous materials or old drugs – do not flush them into your septic system. You may end up contaminating your own drinking water or that of others.

You might see the term “perc test” on listings for vacant land. That means that a test has been performed to make sure that the soil is sandy enough to allow for that percolation process. Clay soils will prevent the liquids from percolating down. In that soil type, special “engineered fields” must be built by digging out large amounts and of the clay and replacing it with gravel and sandy soil (very expensive). Here’s a link to a great EPA article that explains septic fields in much more detail. Print it out and keep it, because it has good advice for living with your septic system – what to do and not to do.

When you are buying a house with a septic system, you should have the septic system tested and the tank pumped out. A good home inspector can do that for you or recommend someone to do it. It adds a little to the inspection cost, but it is worth it for the peace of mind. There are things that can go seriously wrong with septic systems and letting things go to long can result in having to replace the septic tank and field – a very expensive proposition. Regular septic fields can cost $10-15,000 to put in and engineered fields can run upwards of $30-40,000.

As a homeowner you should also be aware of the things that you can do to keep your septic system working properly and the things that you should not do which could shorten its life.  There are great tips for maintaining your system, in the EPA article referenced above.  A well maintained system that is pumped out regularly should last as long as the house; unfortunately many do not because of homeowner neglect or carelessness. For those of you who saw the original movie in the series of films about the Folker family - Meet The Parents – you saw what a failed septic field can do to a yard and a household.

How do I know where my septic tank is located?

Hopefully the seller showed you the location or your home inspector found it as part of the inspection. It is an important thing to know.  If neither happened, you can go to the County Health Department (at least here in Michigan) where location drawings (relative to the house) fields are required to be on file, as well as information about the installation date, tank size and other useful data. That might be especially important if you are considering putting a pool or patio in your yard and don’t want to screw up your septic field in the process. It will also help you to not park on the ground above the field, since that often causes the field pipes to collapse. Also when planting trees in the yard, you don’t want to dig down and hit the field.

Since septic systems are normally paired with wells as the water source, you will also save by not having a sewer charge bill, in addition to no water bill. In the case of the septic you don’t even have an electricity charge; however, remember to budget for that pump out every 3-5 years.