There are various types of septic tanks, drain fields, and drain styles. We will get into briefly what a septic tank is, and answer some questions you may have.
Septic tanks are storage tanks with at least one partition wall — which kind of acts as a filter — that your home's sewage drains into. When in normal use, the tank itself stays almost completely full all the time. So just because your tank looks full, doesn't mean it needs to be pumped.
When does your tank need to be pumped?
Well, every 3 to 5 years is recommended so that the solids that build up get cleaned out. It is also important so that the scum and grease layer on top gets removed, to help your tank and drain field operate as efficiently as possible.
If the tank stays almost full all the time, how does my house drain?
Through the drain field, of course. The outlet side of the septic tank is just slightly lower than the inlet side. Waste collects in the first compartment, solids sink to the bottom, grease floats on top, and the water moves into the second compartment, where remaining solids settle to the bottom and the water then exits the tank.
When the water exits the tank there will be piping leading to the drain field, sometimes going to a distribution box, or manifold, first. The drain field disposes of the waste water into the ground through soil absorption, which is processed naturally. Beautiful isn't it? Okay, so maybe not, but it is neat at least, right?
How long will it last?
Septic systems can last up to 40 years of normal use depending on the type of system installed. Some systems are more efficient than others; some may last only 15 years even with correct installation.
Soil conditions certainly play the biggest role in how long a given system will last, however just as important is how you maintain the system. A septic system is one of the most, if not the most, expensive components of your home, so make sure it's well taken care of.