If you are accustomed to the thought-free ease of city sewer systems, and have recently purchased a home with a septic system, this is a question for which you need an answer! Do not, however, lose sleepless nights fretting about how to care for your septic system. There is really relatively little maintenance beyond learning what not to put down your pipes, and the occasional pumping done by your local septic sewer service professional.
Your septic tank, in essence, is a self-contained wastewater treatment system through which all the water flows from the drains in your home. As the water enters the tank, liquids are separated from solids, the liquid is pumped out into a drainage field while the solids collect on the bottom. Natural bacteria in the tank continues to breakdown the solids, but eventually they will accumulate until they need to be pumped out. How frequently your septic tank requires pumping depends on several factors including the size of the tank, the size of your family (how many people are utilizing water for showers, toilets, laundry, etc.), whether or not you have a garbage disposal and the care you take in preventing the disposal of non-biodegradable waste through your plumbing.
If you have not already established a historical pattern with your septic system that gives you an idea of when septic tank pumping is needed, you may wish to have your septic professional inspect the system yearly to ensure that it is functioning properly and to measure the amount of sludge in the tank. It is recommended that when the sludge level reaches within 6 inches of the outlet pipe, it should be pumped. On average, most septic systems are pumped every one to three years.