Suffolk County Government Crest

Suffolk County Stormwater Management Program

Edward P. Romaine, County Executive

Department of Public Works

Department of Economic Development and Planning

Septic System Failures

Failures within the septic system are usually caused by blockages and clogging from non-dissolved solids. Septic system failures often originate with a failure within the absorption field, which can be caused by crushed or broken pipelines, obstructions or blockages from tree roots, or a blockage within the pipes themselves. The most common source of in-pipe blockages are a result of high volumes of wastewater forcing sludge out of the septic tank and into the distribution system or subsurface treatment system and from sodium overload. Sodium overload occurs when excess sodium chemically bonds with clay particles in an absorption field and forms a water proof barrier around the perforations in the pipes called Hardpan Soil. Both of these failure types result in flooding of your absorption field, which can be disastrous for the species of aerobic bacteria that live in the soil and help treat the effluent as it flows down to the ground water. 

Tips for Identifying a Failing System

Identifying a failing septic system can be difficult to an untrained eye, but there are a few tell-tale signs that one can look out for when trying to determine if a system is failing. The EPA lists slowly draining sinks and toilets, gurgling sounds in the plumbing, constant plumbing backups, sewage odors in the house, or tests showing the presence of bacteria in well water as the first signs of a failing septic system, so if you notice any of these occurring, it would be smart to check outside the house for these signs of potential septic system failure also:

When a septic system fails and untreated effluent is being released into the surrounding soil, the first sign is usually a strong odor. Gases that are released during decomposition processes typically reach the surface first and are easily recognizable. The smell of sewage coming from the ground on your property is a major hint of a problem. The source of the odor will give you a strong indication of where the failure in your system is occurring, and if you are able to determine the source, there are often visual signs in or near that location that will help determine how bad the failure is.

The first visually recognizable sign of a system failure is often given away by extremely vibrant patches of green turf grass or areas where vegetation seems to be flourishing at a much more pronounced rate. This indicates that the soil below is somewhat saturated with effluent from your septic system. Septic effluent is an exceptionally strong fertilizer due to its dissolved nitrate and phosphate content. Seeing this is a strong indicator that you may have a leak in your system. Most people catching a problem at this stage have waited too long already, and may face costly bills for repairs to their system.

vibrant green turf

(Photo: B. Jenkinson, Absorption Field Failure,

The second visual sign of a failure is much more pronounced: the pooling of effluent on the surface of your lawn. If pooling has begun to occur, this typically means the soils surrounding your septic system are completely saturated with untreated effluent. The smell of untreated sewage will be extremely potent and exceptionally hard to miss. This is a serious health hazard for your family and neighbors and a licensed professional should be contacted immediately to assess the situation. Highly saturated soils above your cesspool are often very weak and may be prone to collapse. 

You should never try to enter your septic tank or cesspool, as death or serious injury may occur by drowning or suffocation from gases trapped within the chamber. At this stage of failure, it is highly probable that you may need your entire system replaced, which unfortunately is extremely expensive. In NYS, a typical full septic system replacement may cost between $3000 and $7000 dollars, while a typical inspection and cleaning may cost only a few hundred.

Pooling of Effluent over Failing Septic System

(Photo: Pooling of Effluent over Failing Septic System,

Failures may occur periodically or continuously. It's best to act quickly before you end up getting bogged down. 

If you suspect that your system may be failing and have any questions, you may contact our stormwater specialist:

Scott Curatolo-Wagemann

Stormwater Specialist

3690 Cedar Beach Road, Southold, NY 11971

(631) 852-8660 ext. 32

Also, if you see any of these severe signs above, such as the bright green, flourishing grass, or especially the pooling of sewage effluent on your or a neighbor's lawn, please call the number above or your local health department as soon as possible. If the problem persists for too long, there may end up being a serious problem with Groundwater Contamination.