Whether you’re building a new home or repairing an existing septic system, you may be wondering how necessary a leach field really is. While your septic tank holds the wastewater flowing from your home, it can only hold so much. A leach field is needed to filter out that wastewater. However, when space or environmental sensitivity are concerns, alternative septic systems and leach fields may be an option.
How Does a Septic System Work?
In homes without connection to municipal sewers, septic systems are installed to remove wastewater. As you flush your toilets, take a shower, and even do your laundry, wastewater from your home flows into a septic tank. There, naturally occurring bacteria begin to break down the waste, which is divided into three layers. Solid waste sinks to the bottom, while oil and grease will float to the top. The middle layer is liquid waste, or effluent.
The leach field is an essential part of the system that removes the effluent from the tank and filters it throughout the ground beneath your yard. How does this happen? The liquid waste flows into the drain outlet pipe which leads to a series of perforated pipes. Wastewater then slowly seeps into the soil surrounding the pipes.
Why do you need a Leach Field with a Septic Tank?
Regular septic pumpings are an important part of system maintenance. Without a functioning leach field, however, you’d need to have your tank pumped by a professional much more frequently. If not, wastewater would begin to back up into your drains and toilets. You’d also likely notice an increase in utility costs without a way to filter wastewater efficiently.
Proper wastewater disposal is vital to the environment and communities. For that reason, many states and municipalities have laws and regulations for septic system usage. Most also require a leach field to be used in conjunction with a septic tank.
Situations Where a Leach Field may not be Necessary
Failing the Perc Test
Because a leach field disperses wastewater into the surrounding soil, the soil needs to have the capacity to absorb and retain the water. A percolation test is used to test just that. If the soil surrounding your leach field cannot properly absorb wastewater, it could lead to flooding and other issues. When soil doesn’t pass the perc test, a standard septic system cannot be installed.
Older Septic Systems
A hundred years ago, homes may have been built with septic systems, but not leach fields. Instead of filtering water throughout the yard, the wastewater would often spill into nearby waterways. Clearly, this is not an environmentally friendly or healthy solution today. Because of this, if you purchase an older home that does not have a leach field, you may be required to bring your septic system up to code.
Lack of Space
Most building codes require a specific setback from lot lines and waterways. On rare occasions, the size of the lot may not be large enough to install a leach field that meets those setback regulations. In these situations, an alternative septic system will be needed.
Shallow Water Table
Leach fields must be deep enough below ground to avoid damage from foot traffic or root systems. In areas where the water table is shallow, however, it’s possible for wastewater to flow into groundwater before it’s been properly treated with the microbes in the soil. To avoid groundwater contamination, an alternative septic system will be needed.
Nearby Water Sensitive to Pollution
Contaminated waterways can wreak havoc on delicate ecosystems. If your planned leach field is too close in proximity to a body of water, it will likely violate building codes and cannot be installed.
Alternative Septic Systems
While traditional septic systems are the norm in building homes today, there are a few alternatives that can be used when a leach field cannot be installed. They include:
- Mound Systems
These systems are a possible solution for areas with shallow water tables or dense soil. They are above ground, covered in topsoil, and include a pump chamber to separate scum and sludge, allowing effluent to flow freely into the septic tank. - Aerobic Treatment Systems
For smaller spaces, an aerobic treatment system may be the right choice. With these systems, air is pulled into the septic tank, allowing the natural bacteria to actively clean it. - Sand Filtration Systems
For environmentally sensitive areas, a sand filtration system could be the right choice. Wastewater passes directly through a recirculating sand filter to remove contaminants. It then safely disperses into the soil below. - Evapotranspiration Systems
While this system has a traditional drain field, wastewater does not merge with groundwater. That’s because the base of the drain field is lined with a thick waterproof material that creates a barrier between the wastewater and the soil. When the effluent makes its way through the field, it evaporates instead.
The Importance of a Leach Field
If you have a septic system, you need a way to remove the wastewater from it. In fact, it’s often required by law. In traditional septic systems, this process is effectively performed with a leach field. However, there are some instances when a leach field cannot be installed, including space restrictions, environmental concerns, and soil quality. When using a leach field isn’t possible, you’ll need to consider alternative septic systems. While typically more expensive, these systems are often more environmentally friendly and space conscious.