There are quite a few factors to consider when designing septic tank components. Parameters include the soil’s groundwater absorption rate and the daily volume of wastewater received.
What about the distance between the septic tank and the leach field, though? How far is the leach field from the septic tank supposed to be?
Well, the answer depends on the layout of the septic system, which heavily depends on local zoning regulations. Read on for much-needed insights.
Understanding Septic Tank Components
Here’s an overview of the ins and outs of the septic tank and leach field:
What Is a Septic Tank?
A septic tank is a household’s wastewater treatment facility. It’s built or installed underground and is commonly made of concrete or plastic.
The principles used in its design are relatively simple. It uses natural processes to break down the wastes from bathrooms, kitchens, and laundry.
How Does a Septic Tank Work?
The septic tank is a watertight repository for solid and liquid wastes. Attached to it are two pipes, one of which is the inlet, and the other is the outlet.
The inlet is connected to the household’s wastewater pipes and drains. The outlet, on the other hand, is sloped towards the leach field.
Inside the tank, the wastes settle into three layers over time:
- The solid wastes rest at the bottom and turn into sludge.
- Oil and grease float on the surface layer called the scum.
- The wastewater forms the middle layer.
The middle layer or the wastewater eventually flows through the outlet into the soil and watercourses.
What Is a Leach Field?
The leach field, also known as the drain field or the leach drain, is an assembly of perforated pipes spread out underground and connected to the septic tank’s outlet.
The wastewater leaves the tank through these pipes beneath an open area or field. Then, the water is naturally filtered by the ground before being incorporated back into underground water tables.
Septic Tank and Leach Field Design
The design of a septic system varies by location. Local agencies in charge of wastewater management and zoning agencies direct the design specifications by conducting a soil test.
Through these tests, they’re able to study the ground characteristics and refer to them when designing infrastructures.
From there, they’re able to determine the allowable distances between the septic tank and other structures like foundations and wells.
Does Distance Matter?
In terms of functionality, the distance between the septic tank and the leach field is of little consequence. This means that the leach field could be immediately adjacent to the tank or 100 feet away, and the septic system could still function as it should.
However, a length of 5-10 feet in between is recommended so that if either one needs maintenance or repair, you can do so without damaging the other.
Other Design Parameters
Other conditions matter more than the distance between the septic tank and leach field. These factors include:
- Leach field trench depth, length, and spacing.
- Pipe diameters.
- Gravel or aggregate size.
On top of local zoning laws, the factors mentioned above are designed according to the volume that the treatment facility is estimated to receive daily.
Risks and Hazards of Poor Design
Poor design, such as shallow embedment, pipes laid too close to each other, and insufficient pipe diameter may lead to clogging or seepage.
Read about the signs of a septic system malfunction and how to prevent them below.
What Are the Signs of a Septic System Failure?
To ensure that your plumbing and sanitary lines are in working condition, here are the signs you should look out for:
- Backflow or slow drainage.
- Surface seepage.
- A foul odor around the septic tank or leach field.
- Gurgling sounds on the plumbing lines.
- Damp spots over the septic tank or leach field.
How to Prevent Septic System Failures
Poor design and neglect may lead to septic system problems. Here’s how to avoid them:
Proper Design
During the planning and design stage, make sure that everything is under the laws regulating wastewater management. Consider the size of the tank and the slope of the pipes to avoid backflow.
Additionally, the leach field should be laid out in the recommended depth and spacing. This will prevent surface seepage and, therefore, prevent exposure to sewage.
Regular Maintenance
A residential septic system must be thoroughly inspected every 1-3 years. Still, this depends on the number of occupants in the household and their water habits.
On top of that, the tank should be pumped of accumulated sludge every 3-5 years, or as necessary. You’ll know that the tank is ready to be pumped if the solids fill up two-thirds of its volume capacity.
Recommended Distances From Septic Tank and Leach Field
For the health and safety of the dwellers, there are minimum distances required between residential structures and wells from the septic tank and leach field.
Residential Structure
The septic tank should be no less than 5 feet away from the house. This is to ensure that the tank won’t be damaged or disturbed during construction and repair works.
This will also make the tank more accessible during repair and maintenance. So, make sure that the manhole is free from obstruction for routine maintenance and properly sealed for the rest of the time.
Deep Well
A well should be no less than 50 feet away from a septic tank and 100 feet from the leach field. This distance is enough to keep the well safe from possible contamination, especially if it’s used for drinking.
By neglecting the minimum standards, you could risk exposure to the following health hazards:
- Hepatitis
- Gastroenteritis
- Cholera
- coli
- Shigellosis
Conclusion
How far the leach field from the septic tank is inconsequential to the functionality of the septic system. However, the recommended minimum distance of five feet between them may come in handy during repair or maintenance work.
What’s more important, though, is that the septic system’s design can accommodate the daily volume it’ll receive and is following the local zoning requirements.
Remember that with proper planning and maintenance, our sewage treatment facility can serve us for up to thirty years or more.