Frequently Asked Questions   Back to Septic Systems

My septic system has recently been inspected and the report states that a component of my system “Requires Additional Investigation”. What does this mean?
Typical septic system inspection companies employ technicians whose limited training does not impart the specific knowledge necessary to determine the underlying cause of a problem that may be encountered during the course of an inspection. An engineering assessment is warranted in many circumstances to determine both the cause of the problem and the most appropriate solution. In New Jersey, only a licensed professional engineer can design a septic system.


What is an “ Elevated Liquid Level ”?
A septic system separates liquids from solids. The solids are retained in the septic tank and the liquids are discharged into the soil via a disposal field. A disposal field typically includes laterals laid in either individual trenches or a rectangular disposal bed. The normal liquid operating level in a septic tank or a disposal field is at the lower lip (invert) of the outlet pipe(s).

If an inspector encounters full or partially submerged pipes anywhere in the system he or she will typically make a notation of this fact and discontinue further evaluation of that component of the system. The inspector will then report that component as “Requires Additional Investigation”.


What is a septic system?
A septic system is a subsurface wastewater treatment and disposal system. In most circumstances a septic system will serve only one individual house or building. The sewage from the house enters the system through a building sewer and is treated before being discharged into the ground. Modern systems include a septic tank to retain solids, greases and fats and a disposal field to allow the liquid (effluent) to flow into the ground.


What is a sand mound?
(i.e. raised system, turkey mound, Wisconsin mound)
A sand mound is a system in which the disposal field has been elevated above the original ground surface to account for a high water table, shallow bedrock, or other type of site constraint. A mounded system will normally include a pump tank and pump to lift the effluent up to the raised disposal field.


Is a sand mound more prone to failure than an in ground system?
No. Although a sand mound does include the pump and its associated electrical connections, a properly designed and installed sand mound is no more prone to failure than a conventional septic system.


What is a cesspool?
This is the simplest type of subsurface wastewater treatment and disposal system. A cesspool is common for homes built prior to 1930. The system consists of a pit that has been constructed out of field stone or concrete block. Sewage enters the pit through the building sewer. The liquid level in the pit rises while wastewater is added. The liquid level drops it seeps out of the cesspool and into the surrounding soil.

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How often should I pump my septic tank?
You should pump your septic tank every 2 - 3 years under normal circumstances. If you have a large family you will want to pump the septic tank more often to prevent solids from flowing out of the tank and fouling the disposal field.


I've never had any problems with my septic system, why should I pump my septic tank?
The primary function of the septic tank is to separate liquids from solids. Solids are retained in the tank after settling. Digestion of the solids occurs over time; however, the rate of solids accumulation exceeds the rate of solids digestion. Additionally, not all of the solids are digestible. Therefore, the solids level does rise over several years. A septic tank must be pumped periodically to prevent the solids level from reaching the outlet baffle where they are carried over to the disposal field.


What should I put in my septic system?
A septic system is designed to treat domestic sewage generated through routine wastewater producing activities (i.e. bathing, dishwashing, toilets use, etc.). Do not dispose of harsh chemicals such as pesticides, paint and paint cleaners, solvents, degreasers, etc. in the septic system. The liquid fraction of the wastewater is discharged into the ground. Some organic chemicals will flow untreated through the septic tank and the soil, thus contaminating the underlying groundwater. Do not dispose of condoms, feminine hygiene products, baby wipes or other solid wastes in a septic system. These solids are not digestible and reduce the capacity of the septic tank.


Is it OK to use bleach in my laundry?
When used at the recommended rate household bleach does not produce a high enough residual concentration of chlorine to harm a septic system.


Do I need to add any products (yeast, enzymes, other over the counter additives) to my septic system?
Digestion of the solids that accumulate within the septic tank is a naturally occurring process. The microbes that drive the digestion process are present in raw sewage at a high enough concentration that supplemental products are not normally necessary. However, adding commercially available products will not harm your system.


What is a baffle?
A baffle is an internal component of the septic tank. An inlet baffle directs all sewage towards the bottom of the tank. An outlet baffle prevents floating scum and grease from escaping the septic tank and accumulating in the disposal field.


What rules and regulations govern septic systems?
In New Jersey septic systems are regulated under New Jersey Administrative Code (NJAC) Title 7, Chapter 9A . The NJAC 7:9A Regulations have been in effect since 1990.

Other states have similar sets of regulations. Pennsylvania's program is regulated under Pennsylvania Code, Title 25, Chapters 72 & 73.

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Why are septic systems in New Jersey so expensive?
A combination of factors including design requirements and standards (NJAC 7:9A), subsurface soil conditions, materials costs, and market influences cause the price for a new septic system in New Jersey to represent a significant investment. Most septic systems designed and installed in central and northern New Jersey are classified as soil replacement systems . When these types of systems are installed the native soil is excavated and hauled offsite. Special sand known as select fill is then placed in the hole. A single system may require as much as 400 - 500 tons of select fill. It is not unusual for the materials costs alone to exceed $15,000.

NJAC 7:9A requires that all septic systems be designed by a Licensed Professional Engineer (P.E.). Many municipalities require that the Engineer certify that a system is installed as designed. This requires engineering inspections throughout the construction period. Select fill must be analyzed in a testing laboratory to ensure that it meets the specifications of the design. Further testing is required in the field to verify that the select fill is compacted properly. Health Departments also require that the Engineer prepare a record drawing of the installed system showing ‘as-built' locations of the system components.

Finally, a septic system is sized based upon the number of bedrooms in the home. Many new homes have 4, 5 or even 6 bedrooms. (The greater the number of bedrooms the larger the disposal field - i.e. more select fill.) The septic system must be large enough to accommodate all of the wastewater that would be generated from the dwelling if it were fully occupied.


What is gray water?
Gray water is the portion of sanitary sewage that is not generated from toilets or urinals. This includes laundry wastewater, kitchen sinks, showers, etc. It is not unusual for homes built prior to the 1980's to have a separate septic system that handles the gray water. There are several municipalities in New Jersey that presently require separate gray water systems.


What is black water?
Black water is the portion of sanitary sewage that is generated from toilets and urinals.


Is my septic system going to affect my well water?
Septic systems that have been designed in accordance with the NJAC 7:9A regulations provide at least 4 feet of unsaturated soil that will treat the septic tank effluent to the point where the effluent is clean enough to enter the ground water. Rainfall and melting snow can percolate into the ground and further dilute the effluent. Septic systems are normally located at least 100 feet from wells to provide a factor of safety and ensure that the well water remains clean and potable.

Normally a water well draws water from a deep aquifer that is vertically separated from the ground water into which the septic system discharges. If this is not possible the well can be cased (lined with a solid pipe) to 100 feet to provide the proper separation.

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Can I build or plant anything on top of my septic system?
NJAC 7:9A does not allow construction of swimming pools within 20 feet of a disposal field. Barns, sheds or other structures that are built on slabs may not be erected within 15 feet of a disposal field. Plants or trees with extensive root systems should not be planted within 10 feet of a disposal field. Avoid planting weeping willow trees within 25 feet of a septic system.

As a matter of practicality decks, patios and other structures should not be located over septic tanks or pump tanks. These structures will restrict access to the main lid of the tank making routine pumping difficult or impossible.


The grass above my septic system is a different color than the rest of my lawn. Why is this?
If the grass over your septic system is lush green and the soil is moist, you may have problems with your septic system. You should contact an expert to examine your system to isolate the cause of this condition.

If the grass over the septic system is brown, you most likely do not have enough topsoil to support the lawn's root system.


Should I pump my septic tank before I put my house up for sale?
Routine pumping of a septic tank should occur every 2 - 3 years. If you have followed this schedule, saved the maintenance receipts, and your next regular pumpout will occur during the time your house is on the market there is no problem in having your septic tank pumped. However, if you have not followed a regular maintenance schedule and decide to pump your tank just before the sale of your home it may raise a red flag.

If you are concerned about the condition of your septic system it might make sense to have the system inspected by a reputable company before you put the house on the market. Repairs, if necessary, can then be performed in accordance with a permit issued by the Health Department. The recent repairs and the appropriate documentation may then become a selling feature for your property.


Should I use liquid or powdered laundry detergent?
Powdered detergent comes out of solution and collects in the septic tank. Liquid detergents do not present this potential problem.


I've just been told that my septic system is failing. What do I do now?
Contact a reputable excavation contractor or engineering firm with experience in troubleshooting and correcting septic system problems.

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