Septic Systems 101

Learn about Septic Systems

Did you know 25% of the United States households are on septic systems?

Septic System 101: A Septic System is an Onsite Wastewater Treatment System (OWTS)

A OWTS is basically comprised of two parts or systems

1.) The tank is the first part of your system. The tank is a water tight vessel made out of concrete, fiberglass, plastic often times with a baffle to make it into a two compartment system. Also on the inlet and outlet you have a plumbing T. The T channels everything to drop in the tank for processing, not allowing it to migrate to the second tank. Everything in your house goes to the tank first. The tank is always full of liquid from water, waste, toilet paper, fabric from the wash, and anything else you the homeowner put down the drain.

NOTE: The system is designed to handle digested food waste, not undigested food mater from a food disposal. Every time you flush the toilet or shower or do a load of wash, the amount of water going in to the tank displaces an equal amount which now goes out to the leach field.  The liquid called effluent spills out to the leach field.

2.) The leach field or absorption bed or laterals or Soil Treatment Area, are the second part of your system. It takes the liquid from the tank, and distributes it in pipes that drain it back in to the earth. The earth purifies the water before it reaches the water table. For more info on STA/leach fields click here.

Diagram of Tank and Leach Field (STA) (Picture compliments of Infiltrator Systems)

Why Pump Your Tank?

One of the reasons you pump your tank is to keep the tank working to break down the sludge.  If it gets too full of sludge the system’s ability to work is greatly diminished because the sludge takes up too much room. Another reason you pump the tank is to keep sludge and inorganic particles from building up and migrating out to your field.

Leach fields are the most expensive part of your system costing thousands to replace. The table below shows approximate time you should pump your tank according to how most counties showing how many people in the house and how big your system is. Unless you have a very old system, the county health department should have records of how big your system is and where the tank is, according to the installation drawings we call an as built.

(Learn more about OWTS or Leach Fields.)

Example of How Often to Pump Your Tank

Number of People2 People3 People4 People5 People
750 Gallon Tank2 Years1 Year
1000 Gallon Tank4 Years3 Years4 Years1 Year
1250 Gallon Tank5 Years4 Years3 Years2 Years
1500 Gallon Tank5 Years4 Years3 Years

Onsite Water Treatment Systems Dos and Don’ts


  • Do if possible use a single ply toilet paper.
  • Do spread water usage out. Example, do one load of laundry every couple of days.
  • Do conserve water.
  • Do fix leaky faucets and toilets.
  • Do use cleaning supplies and bleach in moderate amounts. If you are afraid that you are using too many chemicals use Septic Treat to add bacteria back to your septic system. Use of septic treat instead of an over-the-counter treatment like Ridex, is better for your system because it contains no fillers and is stronger.
  • Do pump your tank on a regular basis. Have broken T’s fixed if broken.
  • Do dispose of paint, antifreeze, oil, and other such substances through recycling plant not your septic tank
  • Do use septic treat as a drain cleaner, once a month in a different drain.

OWTS Don’ts

  • Do not overload the system with excessive water.
  • Do not park anything on your leach field due to compaction.
  • Do not plant trees too close to leach field. The roots will infiltrate lateral lines.
  • Do not use a leach field as a pasture for livestock.
  • Do not use your system as a disposal site for any hazardous waste, oil, antifreeze, etc.

Have More Questions?
Ready to have us help you?

Call us at help with your OWTS. 303-526-5370