Proper maintenance for your septic tank is as important as changing the oil in your car. Failure to do so can be just as costly as failure to maintain your engine. Proper maintenance procedure calls for the septic tank to be pumped and visually inspected. However, the frequency with which it must be cleaned depends on the size of the tank, the daily flow of sewage into it from the home, and the number of people it serves. If there is a household garbage disposal in use, more frequent cleaning is necessary.
It is recommended that septic tanks be pumped out every 2 to 5 years, depending on the number of people in the home and the water usage of each family. Obviously the larger the family, the more frequently the tank will need pumping. With ordinary use and care, the tank may need cleaning every 2 to 3 years. The homeowner may ascertain for himself those periods when the tank needs cleaning. It is recommended that when the total depth of scum and solids (see drawing below) exceeds one-quarter of the liquid depth of the tank, the solids should be removed.
Please note, there are no chemicals or digesting yeast products that are capable of reducing the solids in a septic tank to the point where cleaning is unnecessary. Commercial septic tank additives do not eliminate the need for periodic pumping and may be harmful to the absorption field. They can be removed properly only by pumping out the septic tank. Be sure when the septic tank is pumped that it is completely emptied. It is not necessary to retain any of the solids to restart the digestive process. You do not need biological or chemical additives for successful restart or continuous operation of your septic system, nor should you wash or disinfect the tank after having it pumped.
To facilitate cleaning and maintenance operations, identify the location of your septic tank and its leach field or drain field. Keep a copy of the diagram of the septic tank system. It should show the location of the house, the septic tank and manholes or access covers, the piping, and the leaching system. The document will be helpful at the time of pumping or at the time of repairing drain field. Always try to locate a particular fixed landmark to show the distances. If you do not have one of these drawings, you may obtain one from your local building department.
How Septic Tanks Work
Every sink, toilet and shower in your home drains into the septic tank. The septic tank is a watertight box usually made of pre-cast concrete or reinforced fiberglass. When solids enter the tank, (organic solid material) the paper, waste, oils and grease float to the surface, forming a layer commonly called “scum”. Over a period of time, (inorganic solid materials and the by-products of bacterial digestion) the scum deteriorates and sinks to the bottom, creating a layer commonly called “sludge”. Only clear water should exist between the scum and sludge layers and only this clear water in the middle should drain out of the septic tank and into the drain field.
There are several types of drain fields but the two most common are mineral aggregate and chambers. An aggregate drain field consists of a layer of 1 ½” rock, a perforated 4″ diameter pipe laid in a bed of rock over sandy soil. A chambered system is dome shaped with slits on the sides and open on the bottom so it sits flat in the drain field trench. As the liquid exits the tank, it spreads evenly throughout the drain field in a circuit of pipe. The liquid effluent falls from the perforated pipe and is stored in the rock bed until the sand absorbs it.
Eventually, your septic tank will have too many solids in its tank and the septic tank will need to be cleansed of those solids. Some people call this septic tank cleaning while others refer to as septic tank pumping. Regardless of how you refer to it, it is still a necessary and important step in proper septic system maintenance. If your tank is not pumped out regularly, the solids accumulate and the sludge level builds up so that it is eventually forced out into the drain field. It clogs the tiny cracks between the rocks or forms a thick layer on the bottom of the drain trench. This prevents the water from draining out of the septic tank, leading to unsanitary and unsafe conditions. Water follows the path of least resistance. When it is no longer able to exit through the drain field, it will either come up on top of the ground in your yard or it will back up in your home.
When the septic contractor goes to clean out your septic tank, it should be pumped out through the septic system’s manhole, not its smaller inspection ports. Insist on your tank being cleaned through the manhole cover and not the inspection port, as this ensures removal of all of the solids from the septic tank. Be sure that the septic tank is cleaned out completely, with nothing being left in the tank. Any solids or sludge left in the septic tank can clog the drainpipes and cause the need for very expensive repairs in the future.