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NC Department of Health and Human Services
DPH Environmental Health Section
N.C. Public Health Home

On-Site Water Protection Branch

Non-Point Source Pollution Program: System Management for Pollution Prevention

Proper management of on-site septic systems helps prevent pollution and saves money too! Click on the headings below to learn more.

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Pumping the tank really is important

  • If you cannot remember when the tank was last pumped, it is likely time.  The best approach to pumping is to start with a 3 year frequency. 
  • Request that the pumper measure the level of solids accumulation for you so that you can establish a reasonable frequency based upon how you use your system. 
  • Failure to pump the tank can cause clogging of the drainfield and subsequent system malfunction. Surfacing effluent contributes to runoff which contaminates surface water.

The most important piece of real estate on your property is the drain field

  • No driving, building, animal grazing that will crush components or damage soil properties.
  • Establish and maintain a good vegetative cover (preferably grass or low-growing shallow-rooted perennials).  Avoid trees and shrubs with invasive roots that can clog lines.
  • If your permit includes a “Repair Area”, make sure you know the location of this area and that you protect it in case it is ever needed.

The septic system relies on biological activity

  • Avoid harmful inputs such as excessive household cleaners. Chemical wastes such as engine oil, gasoline, pesticides, paints, and solvents should be disposed of through appropriate recycling sites and NOT in the system where they can affect performance.
  • Solid waste such as discarded coffee grounds, grease and cooking oils, sanitary napkins, tampons, disposable diapers, cigarettes, cat box litter, or facial tissues can result in the need for more frequent pumping. 
  • Use of garbage disposals with septic systems is discouraged. It adds extra wastes that do not settle out in the tank. Dispose of food scraps with solid waste or establish a compost pile.
  • Under normal circumstances, the tank receives everything it needs to properly function, so use of additives is not typically needed. Some products may adversely affect the biology in the tank or add chemicals that can contribute to groundwater pollution.

Reasonable water use avoids system overload

  • Your septic system has a limited capacity. If your average daily water use is more than 70% of the design, you may periodically exceed that capacity. If your water is metered, keep track of use for a few months to see how you are doing. Car washing and irrigation water don’t count.
  • Run clothes washers and dishwashers with full loads to reduce the amount of water you send to your system. Spread loads out over time to allow the drainfield to disperse the water from each load. 
  • Plumbing leaks not only waste water (and money!) they may overload the drainfield and cause effluent to surface.
  • Gutters, downspouts, sump pumps and foundation drains are considered clear water sources and should NOT be plumbed into the septic tank; however, diverting drains from clothes or dishwashers to the ground surface or a nearby ditch is illegal and constitutes a Point Source of pollution.

Contact your local health department (PDF, 1.3 MB) if you have questions and/or to report malfunctioning systems.

Non-Point Source Program Information

On-Site Water Protection Branch Information






Updated: January 27, 2020