A septic tank holds wastewater before it enters the drain field, also known as the leach field. Oil and grease float in the top layer of waste, while solids sink to the bottom and form a sludge layer.

A healthy population of bacteria digests contaminants in the septic tank. Using a garbage disposal can increase the amount of solids that clog your septic system. Click here to Learn More.

A drain field is a key part of a septic system that prevents environmental pollution by keeping unpleasant odors and wastewater backups at bay. When properly cared for and maintained, a drain field can last up to 50 years. A drain field (also known as an absorption field) is a series of underground pipes connecting your home to the septic tank.

Essentially, the drain field takes the pre-processed wastewater from the septic tank and spreads it evenly throughout the soil and grass above. The core of a drain field is a series of perforated pipes that are surrounded by a layer of gravel. This gravel acts as a buffer to allow wastewater through, but it also helps keep solid waste from entering the soil and watercourses.

Septic tank drain fields are designed to work with gravity, allowing wastewater to flow through the pipes and into the ground. The septic tank is an oxygen-free environment where bacteria break down the solid waste (such as food scraps and feces) into sludge and liquid. The sludge sinks to the bottom of the tank and the liquid waste (such as soaps, oils and grease) floats to the top. Bacteria in the septic tank use up all the oxygen in this process, so when the tank is full only liquid waste flows out.

The septic tank sends the liquid waste to the drain field via a pipe, which is often buried under the ground and runs along the property line. The drain field is a large, open area of the yard that is usually flat and square, with trenches that are one to three feet deep, four to six feet wide and 100 to 200 feet long.

When the septic tank is not pumped regularly, solid waste enters the drain field and can block the perforated pipes in the leach field. This clogs the drain field and exposes soil, groundwater and surface water to disease-causing organisms from the sewage. The septic tank must be pumped at least every three to five years.

If you live in an area with a high rainfall or rapid snowmelt, the excess water may flood the drain field, interfering with its operation. A flooded drain field will not be able to absorb the wastewater, which may back up into your home and contaminate your indoor plumbing.

Avoid Drain Field Problems

To help prevent problems with your septic system, never flush any kind of solid waste down your toilets or drains, including food scraps, coffee grounds and pet waste. Fats, oils and grease (FOGs) can build up in the septic tank and cause a thick crust that can clog pipes. It is also important to schedule regular septic tank inspections and to have the septic tank pumped when needed.

If you are concerned about how your septic system is working, contact us for a septic tank inspection. We will be happy to inspect the system and recommend services as needed. We can also provide septic tank locating services to ensure that no new construction or landscaping projects are done over your leach field. It is always best to have the tank pumped before doing any landscaping. This protects the septic system from damage and allows for better, more efficient drainage.

Pumps

The pumps that are used to pump septic tanks are not the same as other common household or industrial pumps. Among other things, they are designed to handle sludge and solids, not liquids. In order to properly function they must be well-designed, engineered and manufactured to provide years of energy-efficient and reliable service. There are many different pump types and models available, so the selection process can be a little daunting at first. However, understanding what your pump will need to do can help narrow the choice substantially.

A septic tank pump is typically located in the last chamber of the septic tank or a separate, outside pump station. As the septic tank fills, a float switch is activated and an impeller is engaged. The septic tank pump is powered by an electrical motor and pumps waste up through the outflow pipe and out into your leach or drain field.

The septic tank pump is usually set to discharge a volume of effluent somewhere between the daily flow from the house and one-quarter of the daily flow. For a four bedroom home this amounts to between 150 and 600 gallons of effluent per dose. When the pump is operating correctly, it can be very quiet.

While septic tank pumps are generally very durable, they can be susceptible to damage from certain kinds of waste materials. This is particularly true of commercial or rental applications where there may be more items flushed down the drains. A septic tank filter, also known as a bristle filter, should be installed in front of the pump to protect it from these kinds of contaminants.

For situations where a gravity system cannot be utilized, or for homes that have septic tanks with a high discharge level, a submersible sewage pump can be used. These pumps are usually located in what is called a sump pit and act much like a basement water pump to move standing waste out of the area. It is important to use only quality septic tank pumps in a submersible environment and to consider a grinder pump for applications that require a sewage pump that will grind solids into a slurry and then pump the liquid slurry.

Drain Fields

Septic systems are essential in homes without access to a public sewer system. They are onsite sewage treatment facilities that use pipes and tanks to remove wastewater and then disperse it into the soil.

Wastewater and sewage flow by gravity from your house into a septic tank where solids settle down to form sludge, while oil and grease floats to the top as scum. Compartments and a T-shaped outlet prevent the sludge and scum from exiting into your drain field, ensuring that only liquid wastewater (effluent) leaves the septic tank. The liquid wastewater enters the drain field, where it gets further treated by microbes that work in the anaerobic environment to break down the remaining sludge and scum before it reaches the soil.

The drain field is a series of perforated pipes that are typically surrounded by a porous material like gravel. The pipes are spaced far apart to allow the wastewater time to be evenly distributed throughout the area. This process allows the soil to absorb the effluent, while keeping it from entering into groundwater or surface water sources.

Generally, a drain field can last between 20 and 30 years when it is properly cared for. However, a variety of factors can affect the longevity of your drain field. These include the quality of its initial setup, its proportion to the amount of wastewater it handles, the condition of your soil, and the regularity and type of maintenance undertaken.

Signs that your septic tank drain field may be failing include slow drainage, wastewater backup into sinks, toilets or showers, puddles on the surface of the ground near the septic tank and a foul odor. If you notice these signs, contact a septic service specialist for help with the problem.

To keep your septic drain field in good working order, make sure all gutter downspouts are directed away from the leach line. Keep vehicles, heavy equipment, and grazing animals away from the area, too. It’s also a good idea to avoid building anything over the drain field, including driveways and extra additions to your home. Make sure that trees and plants are not planted over the drain field, too. Lastly, be sure that your septic system is pumped every two to three years. Failure to pump the septic tank will lead to solids being carried into the drain field, where they will clog the pipelines.