What is a Leach Field? 15 Things (2024) You Need To Know

One of the major components of a septic system is a leach field.

While you may understand how a leach field factors into a properly functioning septic tank, you may not realize just how important a leach field is to this system.

In this article, we’ll discuss what a leach field is and how you can prevent and address any major issues.

Let’s get started.

1. What is a leach field?

A leach field is an underground array of perforated pipes that are adjacent to a septic tank.

It is also called a septic tank drain field or a leach drain.

It is responsible for removing contaminants and impurities from liquid after it leaves the septic tank.

For all intents and purposes, it acts as the “disposal filter” for contaminants and liquids after they have been anaerobically digested and passed through the septic tank.

In short, the leach field is where organic material is disposed of.

2. How does a leach field work?

A septic system is made up of three parts: a septic tank, pipes, and leach field.

To understand how a leach field works, you must understand how the septic system works as a whole.

Here are the core elements:

bulletAll waste and wastewater will flow from your house into the septic tank

bulletWaste begins to break down due to the bacteria present in the septic tank

bulletSolid waste will sink to the bottom of the septic tank and become sludge

bulletLiquid waste (fats, oils, and grease) will float to the top of the septic tank and be broken down by bacteria

bulletLiquid waste will then flow into the leach field through underground pipes

bulletSolid waste will remain in the bottom of the septic tank and continually be broken down by bacteria

bulletAs liquid travels through the pipes of the leach field, it will seep into the ground below where it is naturally filtered by the soil

3. Do I have a septic system?

Chances are you’ll already know if you have a septic system.

However, if you’re considering buying a plot of land or you’re new to the septic system world, never fear!

Here are the signs you need to look for to see if you have a septic system.

bulletYou use well water

bulletYou have a waterline coming into your house that doesn’t have a meter

bulletYou show a “$0.00 sewer amount charged” on your water bill or property tax bill

bulletYour neighbors have a septic system

4. How can I find my septic system?

Okay, so you’ve determined that you have a septic system, but you’re not sure where it’s located now.

Here are some of the best ways to locate it.

bulletLook at your home’s “as built” drawing

bulletCheck your yard for lids and manhole covers

bulletContact a septic system provider to help you locate it

5. How to tell if your leach field is failing?

If your leach field is properly maintained, then it will be both invisible and silent.

If your leach field is failing, then it will likely show the following indicators:

bulletPipes that gurgle when being turned on

bulletSlow running drains

bulletPlumbing backups

bulletIssues with toilet flushing (low pressure, slow flushing, not flushing)

bulletSewage odors coming from drains, the septic drains, or leach field

bulletStanding water or wet, mushy grass over the leach field

6. Where is my leach field located?

Leach fields will typically be located in a large, flat, open area of your yard.

Sometimes, they will have multiple trenches between 18 to 36 inches deep, one to three feet wide, and up to 100 feet long.

There are typically six feet between each trench.

If leach fields are properly maintained, they can last up to 25 years.

7. Can you repair a septic drain field?

If you’re having trouble with your leach field, you may be in for a costly repair.

Repairing a clog in a septic drain is relatively straightforward.

Staying on top of this can help prevent more complex and catastrophic problems that arise in your leach field.

More complex repairs will likely be really expensive.

That’s why you’ll want to prevent your leach field from failing.

See the next section for our household plumbing tips that can help with this!

8. How can I prevent my leach field from failing?

If you’re concerned about having your leach field fail, follow these tips.

This will keep your septic system running smoothly!

bulletAvoid pouring grease, chemicals (i.e. bleach and ammonia), or paint down the drain

bulletDon’t flush anything other than bathroom tissue and body fluids

bulletUse the garbage disposal sparingly (if at all)

bulletLimit laundry to one load per day to spread out water usage

bulletDo not park cars, build structures, or place any heavy objects on top of the leach field (check out our do’s and don’ts)

bulletDivert water runoff from excessive rainfall or snow away from the leach field

bulletSchedule regular septic tank pumping every three to five years

bulletView the septic tank pump chart to learn how often you should be pumping your septic tank

bulletCommit to annual septic system inspections and septic service.

9. What are typical septic system leach field problems?

In general, most septic system issues can be traced back to the leach field.

If solid waste or wastewater builds up in the leach field soil, then it will get plugged up and prevent proper drainage.

These problems typically occur when…

bulletYou drain chemicals, paint, grease, and other complex substances that are difficult to filter

bulletYou attempt to process a quantity of wastewater that exceeds the system’s capacity

bulletYour leach field’s top layer is damaged by construction works or vehicles

bulletYou have excessive rainfall or snow that contributes to the amount of water that needs to be filtered

bulletYou have plants and tree roots that interfere with the pipes

bulletYou have pipes that are old, rusty, cracked, or fissured

bulletYou don’t regularly pump your septic tank to remove sludge

Note: the necessary frequency of this can depend on the size and household needs.

Consult a specialist to understand how often your septic tank should be pumped for the best results!

10. When should I call a professional for help with my septic system?

If your septic system is malfunctioning, you may need to call in a professional.

These are the signs that you probably won’t be able to fix the problem yourself.

bulletWastewater backing up into the household drains

bulletBright green, spongy grass in your leach field (especially during dry weather)

bulletPooling water or muddy soil around your septic system or in your basement

bulletA strong odor around the septic tank and leach field

11. What are do’s and don’ts around the leach field?

While many property owners have no problem sharing space with a leach field, there are some do’s and don’ts that come into play when you do this.

Beneath the soil is a complex system of perforated septic pipes and layers of gravel soil.

As a result, you’ll find that most drain fields are flat, open areas that are far away from trees, wells, and other bodies of water.

Below, we’ll run through the do’s and don’ts of what you can do around a drain field.


bulletPlay: Both children and pets can safely run and play on the grass above a leach field.

As long as it is well-maintained, your family shouldn’t have any fear of encountering puddles of affluent or dangerous bacteria.

You can also use bicycles and tricycles on the surface because they are not heavy enough to compress or disturb the soil.

bulletLandscape: Grass is not the best choice of ground cover for a leach field.

However, other options are acceptable.

Look for low-growing plants with non-invasive roots that can grow in place of grass.

They shouldn’t require any maintenance, fertilizer, or irrigation.

Some ideas for plants include sweet woodruff, lamb’s ear, yarrow, and golden sedge.

These look great and fulfill all of the listed requirements.


bulletHeavy traffic: Leach fields are not entirely off-limits to people and pets.

As noted above, they can be an area that children play in.

However, there are some activities that harm its ability to function properly.

Heavy traffic is one of these because it compacts the soil in a drain field, which could break its percolation pipes.

Never graze large animals or ride horses over your leach field.

You also need to keep cars, trucks, farm machinery, and other heavy vehicles away from the field.

So, note, do not turn your leach field into a parking lot!

bulletPermanent covers: Both heavy weights and permanent covers will damage your leach field because of compaction.

This means that you do not want to have a deck, shed, barn, or another edifice over your leach field.

Even cement and gravel walkways can block oxygen from reaching the leach field and prevent the proper breakdown of bacteria.

bulletGardens: Your leach field is a wide-open space, and you may be tempted to use it as a garden.

Why not use it for something useful like crops?

Unfortunately, your leach field is the worst place to do this because the rototilling, fertilizers, irrigation, and deep roots, which are necessary in gardening, are destructive.

Edible vegetables within a leach field also risk exposure to microorganisms.

bulletLandscaping: While landscaping is important near your leach field, you don’t want to drastically adjust any slopes or add/remove retaining walls.

Just be sure to maintain the current landscaping as it is designed to control runoff from your home and the surrounding area.

Don’t go crazy!

Consult an expert because you engage in any intense landscaping activity as it pertains to your leach field.

12. What are leach lines?

Leach lines disperse septic effluent into the ground after it passes through the septic tank.

They are also referred to as leach fields, filter beds, leach beds, and percolation beds.

To disperse the effluent over the field, the leach lines will fan out, trickling through holes in the pipes, and percolating downward through gravel, sand, and then the soil.

Leach lines are typically made of perforated PVC pipe, which encourages the final product to trickle into the soil.

13. What are signs of failing leach lines?

When your septic system fails, it’s important to figure out which part of your system is failing.

Only then can you fix the problem and mitigate it in the future.

Here are the signs of a leach line failure.

bulletIncrease plant growth

bulletGreener grass in other areas of the yard

bulletDrains in the house running slowly

bulletWater in the house frequently backing up

bulletYard is mushy or has standing water

bulletSewage odors either inside or outside of the house

bulletGurgling sounds

Leach lines can fail for a number of reasons.

Sometimes, it may be for a specific reason and other times it may be because your leach field is at the end of its life.

Call in a professional if you’re not sure what’s going on!

14. How do you replace leach lines?

Are leach lines the issue in your septic system?

Do you know you need to replace them in order to repair your system?

Here are the steps that can help you get them sorted as soon as possible.

bulletTear out all existing components in your leach field.

You will require heavy equipment for this step due to the widespread nature of leach fields.

bulletInstall a distribution box near the septic tank.

The distribution box will receive effluent from the septic tank via one large pipe.

bulletRun 4 to 9 lateral pipes out of the distribution box and radiate outward in the trenches to form the leach field.

This is a gravity-based system, so the lateral pipes should run at a downhill slope.

bulletPlace plastic septic chambers over the leach line pipes.

bulletFill trenches with at least 6 inches of dirt (or to the depth specified in your area).

You should select areas at the ends of the pipes, and the distribution box should be kept visible for now.

bulletContact the local permitting office to have them inspect your septic system.

bulletFill in the rest of the trenches once your septic system passes inspection.

15. What’s the life span of a leach field?

Above, we discussed the signs of leach line fails.

When this occurs, you may think that you did something wrong or that you could have done something to prevent this failure.

However, the truth is that leach fields can simply reach the end of their natural life.

Their typical lifespans are roughly 15 to 25 years (although some estimate a little bit longer at 25 to 30 years).

If your leach field is nearing this age, you should anticipate needing to replace leach lines to ensure your septic system continues to work correctly.

Final thoughts

Did you know all that was going on beneath the surface?

Most landowners don’t!

Septic systems are a different way to handle waste, and if you’ve never lived anywhere with a septic system, it’s an entirely new ballgame.

Follow the guidelines above to manage any land you buy with a septic system and leach field.

And for more information on buying, selling, or investing in vacant land, check out our other resources below.

We’re here to help throughout the entire land buying and selling process!

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Erika Gokce Capital

Disclaimer: we are not lawyers, accountants or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.


2 thoughts on “What is a Leach Field? 15 Things (2024) You Need To Know”

  1. Hi Erika,
    Great read on the septic/leach field. natural soil. I am building a new piece of property which includes a septic system. The leach field is located on/in soil that has been cut and back filled. I understand the leach field must be installed in native soil. Do you have any information on this?
    Thanks you,

    • Hello Jack, you should have a perc test done to confirm what is possible on your land and consult with a local engineer, but my understanding is that a septic can be placed in suitable fill.


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