Block Cesspool Collapse Warning

If you have property in eastern Long Island that was developed prior to 1980, there is a good possibility that your underground septic system components (cesspool and/or septic tank) may be deteriorating and subject to collapse.

Up until the late 1970's, most cesspools were constructed of cinder block and brick and in recent years, we've been seeing a major increase in the number of cave-ins. In older cesspools, the mortar, and in some cases, the cinder block, itself, becomes unstable and unable to withstand the constant expansion and contraction of the surrounding soil due to freezing and thawing, super-saturation due to the high water table and even the sudden drop in pressure when the cesspool is pumped out. The result is that an extremely dangerous situation is emerging on properties with older septic systems.

Even where the older cesspools have been replaced with newer and safer, pre-cast concrete cesspools, the old block units may not have been removed or filled in with soil and huge, hollow spaces with weakening domes and walls may exist beneath the surface of your yard or your driveway.

In addition to block constructed cesspools, dry wells can also be problematic, especially if they are underneath driveways or other heavily traffic areas.

"What Can I Do If I Have a Block Constructed Cesspool?"

If your system was installed before 1980, you should identify where all the components are on the property and mark their locations clearly. Keep people, especially children, and pets away from these areas! Never park or drive any vehicle over or close to these locations.

If you must work in these areas, do not do so alone! Some cesspools may be 10 or 12 feet in diameter and up to 12 feet deep. A person falling into the space can easily be injured or suffocated by falling debris, overcome by methane gas or even drowned.

Contact a qualified engineer or licensed septic system service company inspect your septic system, they can advise you of any potential problems.

To avoid problems with your cesspool, you should:

• Know the location of your cesspool(s) and limit foot traffic in these areas. Children and pets should be discouraged from playing above or around the cesspool.
• Close these areas to all vehicular traffic. Do not park heavy equipment, boats etc. in these locations.
• Note any changes in the ground above or near the cesspool. A sudden change in grade (settling), unusual puddling or wetness, odors or sinkholes are all symptomatic of a collapse or other problems. Take all necessary precautions to keep people away from the area and call reputable cesspool service company immediately. At Norsic, we give such calls top priority.
• Consider replacing older systems with a modern septic system that is less susceptible to problems, and far more safe.
• If you are planning a project involving excavation on your property, try to replace the cesspool at the same time. It can save significant time and money.

Call our office at 283-0604, Ext 14, for additional information.

Recent block cesspool collapse. The hole is approximately 3.5 feet in diameter and about the same depth. This unit was located in the front yard but fortunately, the collapse occurred without anyone nearby.

The same collapse from another angle showing the concrete "flat top". Had a young child been playing here, this collapse could have caused serious injury or even death.

In this photo, the technician measures the depth of a collapse in the parking lot of a restaurant. In this case the unit is a grease trap, which is a component of septic systems usually found in situations where there are large, commercial kitchens.

Here, the collapse has progressed to about six inches below grade and if left uncorrected, a complete cave-in will eventually occur. The situation is made all the more serious by the fact that the unit is located under a spot exposed to vehicular traffic. This needs immediate attention.