Throughout America, millions of city dwellers take for granted that they can flush the toilet and everything in it will disappear into the sewer.

Country properties, however, usually dispose of sewage with a septic system. Through a rather unsophisticated combination of a holding tank and perforated pipes called leach lines, the sewage is absorbed (leached) into the ground.

As you might imagine, there are all kinds of ways for things to go wrong with such a system. When your septic tank backs up, or your leach lines become plugged, septic tanks are no fun. That's why it's a good idea to make sure the septic system is working properly before you firmly commit to buying your country dream. As with the water potability tests mentioned above, your lender may require a septic system inspection and certification before lending on country property.

A septic system inspection usually includes a visual inspection of the area around the system to look for obvious leaks. Such system failures are usually detected by visual clues of seepage and the accompanying malodorous stench. The inspection also should include pumping the contents from the tank and a visual inspection of the inside of the septic tank after the pumping is completed. This inspection should reveal any cracks or flaws in the tank itself. If the system is in good working order, you should receive a written certification stating the results of the inspection.

If you're considering the purchase of vacant land, you should perform soils tests to determine the feasibility of a septic system on the property. Those tests vary from area to area, depending upon the requirements of the local public health officials. If the land under consideration is located in an environmentally sensitive area, such as near a year-round stream, plan to meet more even more stringent requirements.

Soils tests will reveal what kind of soil you have at the depth where your septic system will be placed. For a septic system to work, the soil must be capable of absorbing the waste from your septic system. If the soil is too porous, or sandy, waste materials will pass through too quickly for nature to purify them. The opposite extreme, such as rocky soil or hardpan clay, will not permit waste materials to pass through quickly enough to be purified. A happy medium is necessary for a septic system to work effectively.

Most health officials will want to see the results of a percolation test, also known as a "perc test," to verify the rate of absorption for the soils where you intend to place your septic system prior to approving a building permit. A percolation test usually consists of boring several holes with a power auger, filling them with water, and observing the elapsed time for the water to be absorbed into the ground.

Some health officials also may require a soil mantle test, done by digging a deep trench with a backhoe tractor. By digging a trench several feet deep, health officials can better examine the makeup and quality of subsurface soils and decide how well your land will accommodate a septic system.