Septic Terms and Definitions

Terms and Definitions

Alarm – Located near the house or a facility, these are important early warning systems that can alert someone when a potential overflow is about to happen.

ATU – Aerobic Treatment Unit – See our section on ATU’s

Baffle – Most septic tanks and grease traps contain baffles that split the tank in two sections with a small area for effluent to pass through at a high spot in the baffle. The purpose of the baffle is to let the solids in the incoming effluent settle out to the bottom or float to the surface, and to lessen the impact of stirring up the tank when new effluent enters.

Clean-out – These are simply tee-sections of pipe that are placed in line of a gravity pipe to allow access to it from above. It will be topped with a screw-on top and can be used to inspect or clean the pipe. Typically a septic system will have a clean-out installed between the septic tank and house.

D-Box or Distribution Box – This is a small box typically with 4” holes on all sides of it that is located at the end of the outlet pipe between the septic tank and drainfield. It is used to evenly distribute the exiting effluent from the septic tank on its way to the drainfield. It is usually made of plastic or concrete, but in many newer systems it has been replaced with a header system.

Drainfield – Also known as the leachfield or absorption field, this portion of a septic system is designed to evenly distribute the effluent leaving a septic tank across a large area through underground pipes or chambers to let the effluent absorb into the soils. The drainfield can be made of rock, perforated pipes or open chambers all buried underground.

Effluent – The discharge of wastewater from any home or facility is considered effluent.

Exfiltration – When sewer pipes have holes or cracks in them from shifting ground, root intrusion, poor installation, etc. the wastewater flowing through them will leak out into the environment.

Filter – A septic filter should be installed on the outlet side of the septic tank to protect the drainfield from solids getting in and clogging its ability to absorb water. If enough solids enter the drainfield it can ruin the drainfield costing thousands of dollars to repair or replace. A filter should be cleaned at least once a year to prevent it from clogging up and causing the effluent to backup into the house.

Float Switch – These typically come in the form of 2 to 3 inch diameter round balls connected to wires. These balls are designed to act like switches so that when the ball begins to float and flip over a gravity activated switch inside sends a signal to the control panel that something is happening. Depending on how the float switch is wired the control panel will turn on or off another device such as an alarm or pump. There are different types of float switches that play different roles depending on how they are wired to the control panel. There can be as many as five float switches in a large pump tank, but a typical home will only have two: the start float and the alarm float (for more information on the other float types see our section on Sewer / Lift Stations). The start float turns the pump on when the level of the effluent reaches a high point in the tank and then turns off when the level comes back down. The alarm float triggers the alarm(typically part of the control panel) when the effluent level reaches too high in the tank threatening to overflow it.

Grease Trap – See our section on Grease Traps

Header System – This system of 4” pipes is located between the septic tank and drainfield as a newer alternative to a distribution box. It consists of a single pipe leading from the tank to a tee-section where the water is distributed equally across multiple pipes to dose the drainfield evenly.

Infiltration – When sewer pipes have holes or cracks in them from shifting ground, root intrusion, poor installation, etc. groundwater will sometimes leak into the sewer system.

Inlet – In an underground tank, such as a septic tank or grease trap, the inlet is the hole in the wall of the tank where the pipe flowing from upstream enters into the tank. This is where the effluent enters the tank as opposed to the outlet where it exits the tank.

Inspection Port – These are typically installed in line after a grease trap in the form of a small box that the effluent collects in briefly before passing through. It should be easily accessed for county or city inspectors to collect a sample of the wastewater for testing purposes.

Jet Job – Classified as a rejuvenation of a drainfield and requiring a permit by the State of Florida Department of Health. A jet job is performed when a drainfield is failing to absorb the effluent flowing into it because of minor root intrusion or because of solids entering the drainfield. It is performed by means of digging up the section of the system between the septic tank and drainfield and using a highpressured water jetting system to flush out each individual line to remove blockage.

Jetting, Line – A service performed on any sized pipe where a high-pressure line is inserted into the pipe and it jets water backward toward the opening. As the line moves down the pipe it scours, cleans, and pushes the debris back out of the pipe to be removed, usually by a vacuum-truck. This service is usually performed to remove dirt or grease that has built up in the pipe over a period of time.

Lid, Tank – Lids come in various sizes all for different purposes. The typical septic tank lid will be in three separate sections (called a sectional lid) that rest on top of the septic tank. Lids also come in small round sizes that fit over risers, as well as large sizes with access ports that cover the entire septic tank with one section. Typical lids are not weight rated to hold anything very heavy, such as cars, and will crack or collapse if driven over. Traffic rated lids, similar to those used on grease traps, can be purchased.

Lift Station – See our section on Sewer / Lift Stations

Manhole – These are cylindrical concrete structures that are placed periodically along a stretch of sewer pipe or at every turn in the pipe to allow access to the pipe from above. The wastewater does not pool in these structures, but passes continuously through them.

Outlet – In an underground tank, such as a septic tank or grease trap, the outlet is the hole in the wall of the tank where the pipe flowing downstream leaves the tank. This is where the effluent exits the tank as opposed to the inlet where it enters the tank.

Pipe Inspection, Video – Small, specialized, water-proof cameras that send signals back to a control system can be used to investigate pipes as small as 4”. These cameras come in the form of push cameras on a rigid cable or large robotic crawler cameras that drive by remote control along the inside of pipes. The cameras are used t o determine where infiltration and exfiltration may be taking place in the pipe, searching for crushed or damaged pipes, as well as confirming that pipes have been cleaned thoroughly.

Pump, Effluent – For homes that require a pump station because of the need for an elevated drainfield the pump station will contain a small pump operated by a control panel and float switches to pump the effluent up-hill into the raised drainfield. The average home will only need a 1/3 HP or 1/4 HP pump.

Pump Tank or Pump Station – This is sometimes referred to as a STEP(Septic Tank Effluent Pump) system, and is similar to a lift station on a smaller, simpler scale. The pump tank is located between the septic tank and the drainfield when situations require that the drainfield be at a higher elevation than the outlet of the septic tank. The pump tank is a smaller sized tank that the effluent from the septic tank flows into. It contains a pump at the bottom that will pump the effluent up into the raised drainfield when the effluent level reaches a certain point that triggers a float switch.

Rails, Pump – See our section on Sewer / Lift Stations

Real Estate Inspection – See our section on Septic Inspections

Riser – These are round rings about 24” in diameter made from plastic or concrete that brings the level of access to a septic tank or grease trap to the level of the ground. They are required on all grease traps if not at grade and should be installed on all septic tanks whose lid is deeper than 3 inches. Risers make access for pumping and maintenance much easier.

Septic Tank – These are typically sized around 1,000 gallons and can be made from concrete or plastic. This tank is the first step in the process of cleaning household wastewater on-site. It traps solids and floatable materials in the first baffled section allowing the effluent to pass into the second section of the tank by gravity where it exits the outlet. Every time wastewater enters the tank an equal amount of wastewater exits the tank out the other end. A septic tank also contains natural bacteria that feed off the wastewater helping to break down the contents. A septic tank that is working properly will always be full and for the typical household it will fill up again within about 48 hours after you have it pumped out. Septic Tanks should be pumped out at least every 3 years, but for best results in protecting the drainfield it should be pumped out every year.

Septic System – See our section on Septic Systems

Sewer, Gravity or Forcemain – See our section on Sewer / Lift Stations

System Inspection – See our section on Septic Inspections

System Verification – See our section on Septic Inspections

Terra-lift – Classified as a rejuvenation of a drainfield and requiring a permit by the State of Florida Department of Health. A terra-lift is performed when a drainfield is failing to absorb the effluent flowing into it because of a biological build up of wastes in the soils that prevent them from absorbing the effluent entering the drainfield. It is performed by means of a terra-lift machine that is driven over the drainfield in order to inject air and foam beads into the soils below the drainfield in order to crack the soils open allowing effluent to begin seeping in like normal.

Valve Box – These are typically part of a lift station and come in the form of a sunken concrete vault with opening top doors to allow operator access. The Forcemain piping from the pumps in the lift station will pass through this box. As the pipes pass through they will have check valves, plug valves, pressure gauges, and emergency pump cam-locks that technicians can use to monitor or manage the system.