If you are dealing with a job where a typical pipe-and-gravel septic system can t be used, you are faced with chamber-type systems and other special-use systems. Any of these systems will typically cost more to install than a simple pipe-and-gravel system. The specific type of system used will depend greatly on existing soil conditions. Choosing a special-use system is rarely left to the discretion of a builder. Engineers and county officials are normally the ones to dictate what type of special system will be used.

There are four common types of special-use septic systems. Chamber systems are the most common. Trench systems are usually the most inexpensive type of special-use system available. A mound system might be prescribed, and there are times when a pump system is required. Your installation cost with any of these systems is likely to be higher than what you might expect.

Before moving north, I d never encountered a chamber system. The soil in Virginia tended to be well suited to septic systems, so gravel-and-pipe systems were normally installed. Pump systems were required occasionally, but chamber systems were never required on any of my jobs in Virginia. While they were very unusual in Virginia, they account for a large number of systems in Maine.

My personal experience with septic systems is limited to the East Coast. I don t have first-hand experience with other parts of the country. However, a little research on your part will reveal the types of systems that are the most common in...