Septic Systems: Preventing a Stink

Septic systems vary according to site and soil characteristics and the space available. Know what style is connected to the house you are considering. In addition to the conventional system, there are some requiring pumps because the drain field is higher than the tank. Others use sand filtering, while still others are built in mounds on the ground's surface, usually because of poorly draining soil.

¿ What is the tank made of? Older steel tanks can rust through. Concrete tanks seem to be the norm, but plastic ones are easier to move to sites with difficult access.

¿ How old is the system? If built properly and maintained regularly, septic systems can last decades. County health departments often have records of the construction date, location and original contractor, but not all systems are so recorded, so you may have to rely on information from previous owners.

¿ Will the size of the tank and drain field meet your family's needs? When a septic system is built, its original size is determined by how many bedrooms a house has, with the assumption that there will be two occupants per bedroom. The system's distance from the house and any wells is determined by state and local regulations.

¿ What kind of use has the system had? Have there been additions to the house? A four-bedroom house occupied by an elderly couple is not going to challenge a septic system as much as the same house occupied by two parents and four teenagers. Houses that evolve from seasonal to year-round residency may not have sufficient systems for the expanded use.

If the tank is too small for your needs, heavy water use flushes the system before the separation and decomposition process has a chance to work. Online calculators can help you determine what size and capacity are best for your family.

Two-compartment tanks, which allow waste a second settling before it heads out to the drain field, are popular. They add a few hundred dollars to the cost of a single-chamber tank. "It's like a cheap insurance policy," said Rick Colson of Fogle's Septic Service in Sykesville, Md.

The size of the drain field depends not only on the size of the house but also on the type of soil. Clay soil requires a larger field because its absorption is much slower than sandy soil. Steep, rocky slopes require a different configuration than flat ground with porous soil.

¿ Has the septic system been maintained regularly? One Earlysville, Va., resident, who has lived in her house for eight years, wrote in an e-mail: "We've never had the septic cleaned out or anything. Don't even know when it was done, if ever, before we bought the house, which is about 32 yrs old now. Kind of scary."

That's an understatement. Regular maintenance of a septic system usually runs less than $300 every couple of years. Repairs to or replacement of a failed system can cost thousands. In addition, a failing system can affect local well water.

If a septic tank hasn't been pumped out for years, sludge can rise too high, entering the effluent exit pipe and resulting in unsettled solids being pushed into the drain field.

Broken pipes can also allow sewage to discharge before proper treatment is complete.