Septic systems in North Carolina and Asheville NC

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Remember that information can always become out of date or subject to new legislation - if you are buying a home be sure to have the septic system inspected by a professional in that area.

If you use a septic system, or if you are buying a home with a septic system, this owner's guide can help you be sure that your septic system is used and maintained properly. This folder also provides a place to record and keep important information, such as a copy of your permit, a sketch of your system, maintenance records, and other fact sheets.

Know the Ins and Outs of Your System

What Type of System Do You Have?

Many different kinds of septic systems are used in North Carolina, but most of the 1.2 million systems used are slight modifications of the conventional septic system. This type has a septic tank and a drainfield with gravel-filled trenches (usually two to six trenches).

Cooperative Extension Service publication (AG-439-13) Septic Systems and Their Maintenance describes the conventional system and important maintenance needs for it.

Other types of systems include pump to conventional systems, pressure manifold systems, low pressure pipe (LPP) systems, and aerobic treatment unit (ATU) systems. These types of systems normally have pumps, electrical floats and controls, alarms, or other mechanical parts that are sure to fail without maintenance. For this reason, state rules have specific maintenance requirements for a number of these systems.

Your local Health Department can tell you what type of system you have and what legal requirements there are for long-term maintenance of that system. You may be required to have an operation permit from the Health Department and a maintenance contract with an approved "management entity" (organization). The management organization could be a certified septic system operator or a public agency involved in wastewater management. These activities will result in monthly or yearly system maintenance fees for homeowners, but they also should help improve the longevity and performance of these systems.

Things You Need to Know About Your Septic System

  • What type of septic system do you have?
  • Where is it located?
  • Where is the repair area located?
  • Is the septic system working properly?
  • Has It been maintained in the past?
  • What can you do on a day-to-day basis to keep your system working properly?
  • What maintenance is needed in the future?

Do You Know the Location of Your Septic System and Repair Area?

To properly maintain your septic system, you should know the location of both the septic tank and the drainfield. Contact the local Health Department for a copy of your septic system permit and soil evaluation sheet, which will indicate the approximate location of the system and the size of the tank. Keep these items in a file folder.

A good starting point for finding the tank is to look in the crawl space to see the direction in which the house sewer pipe enters the soil. Then, gently push a thin (3/8- to 1/2-inch diameter) steel rod into the soil to feel for the tank about 10 feet away from the house. Of course, you should first call local utility companies to make sure there are not any underground utilities (such as buried electrical cables) in the area.

Most housing sites are legally required to have a repair area in which a second drainfield could be built if needed. This repair area is identified when the site is permitted. The law also requires you to protect this area from excavation, building, swimming pool construction, and other land-moving activities.

Sketch your home, septic system, repair area, and other important features (such as your driveway) on the grid labeled Septic System Layout. When you have your septic tank pumped, measure and record the distance from the house to the access port on the tank. This will help you find it again. You may also wish to mark the location of your tank and boundaries of your drainfield in your yard.

Septic System Layout

Is Your Septic System Working Properly?

Unfortunately, if house fixtures drain well, many people are not concerned about whether their septic system is working properly. They don't realize that untreated sewage can be a health hazard. If your system shows signs of problems, contact your local Health Department immediately. They will diagnose the problem and prescribe changes or additions that must be made to repair the system.

State law requires that you get a permit from the Health Department before repairing a failing septic system. It is important that the system is repaired as soon as possible to minimize the health risk to your family and community.

What Maintenance Has Been Done?

Before planning a maintenance program, find out what maintenance has already been done. If you are buying an existing home, ask the seller a few important questions such as:

  • How old is the system?
  • When was the tank last pumped?
  • How frequently has it been pumped?
  • Have there been signs of possible failure?
  • Have there been additions made to the house that would necessitate increasing the size of the system?

If the house has just been built, ask the septic system contractor to provide you an "as built" diagram that may show details not on the permit. If you have an LPP system, ask the contractor and Health Department to provide details concerning the initial pump delivery rate and pressure head they set up when the pressure distribution network was approved for use.

Proper care of your septic system requires day-to-day management as well as periodic maintenance and repairs.


Day-to Day-Management

Don't use too much water.

  • The drainfield does not have unlimited capacity.
    • The typical daily water use is 50 gallons per person.
    • The soil drainfield has a maximum design capacity of 120 gallons per bedroom. When near capacity, systems may not work.
    • Overloads can occur seasonally or daily.
    • Water conservation will extend the life of your system.

Limit disposal to sewage. 

  • Don't use your septic tank as a trash can for cigarette butts, tissues, sanitary napkins, cotton swabs, cat box litter, coffee grinds, or disposable diapers.
    • Restrict the use of your garbage disposal.
    • Don't put grease or cooking oil into the system.
  • Don't poison your system with harmful chemicals such as solvents, oils, paints, thinners, disinfectants, pesticides, poisons, and other substances. They can kill bacteria that help purify sewage and can also contaminate groundwater.
  • Save money. Commercial septic tank additives are not necessary. The bacteria needed for partially decomposing the tank solids are naturally present in sewage. Even if you use additives, you will still need to pump the solids out of your tank.

Protect the system from physical damage.

  • Keep the soil over the drainfield covered with vegetation to prevent soil erosion.
    • Be careful not to mow the lateral turnups off of LPP systems.
    • Don't drive heavy vehicles over the system.
    • Avoid construction over the system and repair area.
    • Maintain the natural shape of the land immediately downslope of the system, and protect this area from excavation (cutting and filling).
    • Don't cover the tank or drainfield with asphalt or concrete.

Dispose of all wastewater in an approved system.

  • Don't put in a separate pipe to carry wash waters to a side ditch or the woods. This graywater contains germs that can spread disease.
Preventive Maintenance Record
Date Work Done Firm Cost


Your Septic System Installer
Date System Installed


Your Septic System Pumper


Periodic Maintenance and Repair

Home and Yard: 

  • Repair dripping faucets and toilets.
    • Cut down and remove trees that like wet conditions. Treat the stumps to prevent further growth.
    • Landscape the yard to divert surface waters away from the tank and drainfield.
    • Be sure that the water from the roof, gutters, and foundation drains does not flow over the system.
    • Install an interceptor ditch, if needed.
    • Maintain drainage ditches, subsurface tiles, and drainage outlets so that water can flow freely.

Septic Tank: 

  • Install a concrete riser (or manhole) over the tank if it is buried 6 inches or deeper, to provide easy access for measuring and pumping solids.
  • Keep track of how quickly sludge and scum accumulate in the tank.
  • Have solids pumped out of the tank as needed.
  • Don't wait until your drainfield fails to have your tank pumped. By then, the drainfield may be ruined. With septic systems, an ounce of prevention is worth a ton of cure!
  • Cooperative Extension Service publication AG-439-13, Septic Systems and Their Maintenance, contains more information on pumping frequency.

Regulations and Precautions: 

  • Hire a certified operator when required by law, as in these cases:
  • Low pressure pipe (LPP) systems installed or repaired after July 1, 1992.
  • Aerobic treatment unit systems.
  • Some other complex systems.
  • Be sure the pump, electrical controls, floats, and alarm on your LPP, ATU, pump to conventional, or pressure manifold system continue working properly between scheduled maintenance visits.
  • Work carefully and safely. Sewage contains germs that can cause diseases. Never enter a septic tank. Toxic and explosive gases in the tank present a hazard. Old tanks may collapse. Electrical controls present a shock and spark hazard. Secure the septic tank lid so that children cannot open it. 
  • Don't attempt to repair a failing system yourself. Get a repair permit from the Health Department and hire an experienced contractor.

Signs of Possible Septic System Problems

  • Sewage backing up into your toilets, tubs, or sinks.
  • Slowly draining fixtures; particularly after it has rained.
  • The smell of raw sewage accompanied by extremely soggy soil over sewage discharged over the ground or in nearby ditches or woods. Note, in the LPP system sewage may come to the ground surface when the pump is turned on and then disappear after the pump turns off.
  • Broken or cracked white pipes that stick out of the ground in a LPP system.
  • An alarm flashing (red light) or beeping in the  house, space, or in the yard indicating a pump is not working properly.
  • An increase in infections or illnesses associated with swimming in lakes or rivers next to the system.
    • Water test results indicating the presence of biological contamination or organic chemical contamination in the groundwater under the system.


For more information about septic systems, contact your county Cooperative Extension Service center. The following publications are available:

AG-439-11, Soilfacts: Management of Single Family and Small Community Wastewater Treatment and Disposal Systems
AG-439-12, Soilfacts: Investigate Before You Invest
AG-439-13, Soilfacts: Septic Systems and Their Maintenance
About Septic Systems: What You Need to Know


This fact sheet is based upon a concept used by Dersch and Rhoads of the Michigan State University Cooperative Extension Service and Lopes of the University of Massachusetts Cooperative Extension Service.

The North Carolina Department of Environment, Health, and Natural Resources (Division of Environmental Health), members of the On-Site Sewage Program Advisory Committee, and local county Extension and Health Department Staff members provided technical review and valuable input.

This publication was supported in part by the North Carolina Septic Tank Association.


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