Septic Tank Inspections.  Because the septic tank and drainfield at a property are buried, thus hidden from view, because these components are expensive to replace, and because a costly problem can be present but not obvious, it is important to understand the septic system and to inspect and test it when buying a property served by its own private septic tank.
Septic systems include buried septic tanks (sewage tanks) and drainfields – expensive and hidden from view such as in the photo above. This document provides advice for home buyers who are buying a home with a private septic system: homes using a septic tank and drainfield or similar soil absorption system.
Other chapters of this guide explain what goes wrong with septic systems, 5-recommends and describes septic inspection and test methods in more detail, explains how to be sure your septic inspection and septic test are conducted properly, tells you where to get more septic system information about a given property, and warns of unsanitary or dangerous site conditions.
If you need to know how to install a septic system, or if you find that you have a sewage pit (cesspool) this website provides articles explaining those topics too.
This schematic of a conventional two-compartment septic tank (below) illustrates the first of two major septic system parts: the septic treatment tank..
Home buyers ask us these questions about septic systems:
• What is a Septic Tank?
• What is a Leach Field?
• How does a septic system work?
• What does the existing septic system consist of at my new home?
• Do I have a Cesspool or Drywell?
• How do I know if the septic system is working properly?
• What septic inspections and tests should I have performed when I am buying a home?
• How long will a septic system last?
• Is septic system maintenance necessary?”

To help buyers obtain the necessary information to address these questions, we have put together this document to guide them in making informed decisions regarding the potential problems and costs associated with a property’s septic system.
2-YOU NEED TO KNOW AND DO: How Septic Systems Work. Here is the minimum you need to know and what you need to do (or have done) when buying a property with a septic system
Our sketch below shows the second major portion of a septic system: the effluent disposal or drainfield or soakaway bed that disposes of clarified effluent liquid waste that leaves the septic tank.

So how does a septic system work? A private onsite septic system means that the waste from your building drains (sinks, showers, toilets) goes into a septic tank which retains the solids and lets the effluent flow into the soils on the property.

Properly designed and installed these systems are functional and sanitary. Private septic systems serve more homes in the U.S. and many other countries than any other waste disposal method. But the components are costly and do not have an indefinite life.

Because of the potential repair/replacement costs involved, and because the system is buried and cannot be exhaustively inspected and tested, you want to do what you can to evaluate the condition of the septic system before you complete the purchase of the property.

Here’s what to do: If you are buying a home with a septic tank and drain field, here’s what you need to do, as succinctly as possible. Each of these steps is described in more detail below, and in even more detail in linked-to documents.

Steps 1 and 2 are essential. Step 3 is usually a good idea. Step 4 depends on the results of steps 1,2,3 but is usually a good idea. Step 5 is not usually done but might be necessary. Step 6 is what you do if you’re being really thorough.

Synonyms for “septic system” used by the general public include septic waste system, sewage systems, and water sewage systems, even Roman sewage systems. All of these refer to onsite systems which hold and separate sewage waste from its liquid effluent which is treated further and then disposed-of by any of a variety of means which we will discuss. At this site we also discuss special considerations for handling septic waste such as garbage disposal septic tank waste volume and what to do about it. Perform these steps in the order we list them. (For example, don’t pump the tank before a loading and dye test.)
1. Ask About the Septic System – where is it, what’s installed, what’s the service and repair history
2. Make a Visual Site Inspection for signs of trouble. If you can find the tank, for safety, be sure that there is no evidence of collapse or subsidence on the property, and be sure that the septic tank (or cesspool, or drywell) has a safe cover so that no one can fall into the tank. See SEPTIC TANK COVERS for details.
3. Perform a Septic Loading & Dye Test to see if it produces evidence of a failure. Hire a home inspector who knows how to perform and will include this test.
4. Pump the Septic Tank and inspect for additional clues, depending on what you learned at 1,2,3.
5. Additional Septic System Physical Investigation might be needed
6. Get Outside Information Sources about Septic Systems if you’re being really thorough
7. Neighboring Septic System Problems – advice for dealing with a neighboring septic system producing odors or seepage.

For some recommend septic tank inspectors visit Barrie Home Inspector for contact details.