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Aging Septic Systems

House Doctor | Gary Dymski

December 13, 2001

Q. I am considering replacing our cesspool, and I would appreciate any suggestions you may have.

I live in Commack, in the Town of Smithtown. I am almost certain that our cesspool is block construction. It has been pumped several times and chemicals have been added. The most recent pumping was about a year ago, at which time it also was aerated. It apparently needs service again, because our slop sink in the basement fills up after we run our clothes washer or dishwasher.

A while ago, you wrote about the collapse of a cesspool. Rather than just pumping again and risking a collapse, I am thinking of replacing it. Our house was built in 1958, and we moved into it in 1978. Is a septic tank better than a cesspool? Is one more expensive than the other? How big a cesspool should I get for my home? Where can I go to get information?

-W., Commack

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A. First, you definitely should make a new sewage disposal system a priority, and, according to the standards set by Suffolk County, you must install a septic tank and a leaching tank. The airtight septic tank stores three layers, a solid layer, a scum layer and a clear liquid. As the tank fills, the clear liquid that is formed by bacteria and enzymes liquid flows into the leeching tank, where it can be dispersed into the soil. County code prohibits sewage tanks built from blocks or two cesspools.

You can get a free pamphlet, "Home Sewage Disposal Systems in Suffolk County," from the county department of health services (631-852-2100). You might also request from the department a free booklet that covers standards for construction of sewage disposal systems for single-family residences. This is more detailed information, designed for businesses that install and maintain septic tanks.

Your current system is probably on its last breath. "I advise homeowners in this situation to always upgrade their current system if they can afford it," said Roy Reynolds, an engineer with the Suffolk County Deptartment of Health Services. " ... In this person's case, contractors are going to continually try to retrofit the existing system." Translation: You're going to pay more and more each year to maintain your present disposal system, and you might very well be risking its collapse.

Another bit of advice: Be sure the contractor you select to build your system has a liquid waste license from Suffolk County Consumer Affairs. According to William Baessler, director of the bureau of licensing, the liquid waste license is a couple of years old and is required for any business that hauls, installs or maintains sewage disposal systems in the county.

As for size, you'll probably need a septic tank that holds between 900 and 1,250 gallons. But tank size depends on several things, including type of soil around the tank and the average daily flow of waste (in gallons). Rely on your contractor for the best advice.

As you research installation of a new system, make sure you take care of your old cesspool. Reynolds says it's best to have block cesspools filled in with sand, then covered with topsoil. Make sure your contractor can do this job.

Finally, visit Dan Friedman's All Septic System Information Web site (www.inspect-ny.com/septbook .htm) or the Cornell Cooperative Extension's page on septic tank maintenance (www.human.cornell.edu/ txa/extension/wq/maintenance.cfm). Friedman, a home inspector and contractor, also has several links and online articles about chemicals and tank maintenance. It's a great site.