We love trees, and we always love when property owners plant and care for trees on their property. However, there is one place where we strongly discourage planting or letting trees grow – leach fields. Leach fields, or septic drain fields, can easily be damaged by trees, tree roots, and the equipment needed to maintain or remove a tree, leaving you with an expensive (and disruptive!) problem.
These FAQs will answer questions you may have about why trees and leach fields don’t mix, such as:
- why and how trees end up growing in septic system leach fields (especially if you didn’t plant them there),
- why leach fields are no place for trees,
- how removing a tree from a leach field can cause major problems (and why that can be so expensive),
- the worst things to plant in or near a leach field, and
- what we recommend planting in that area for better visual appeal without the headaches.
FAQs About Trees Growing in or Near Leach Fields
We often see trees happily growing near septic systems – and the unhappy homeowners who have to deal with the problems caused by those trees. To (hopefully) prevent those problems, we’ve put together answers to the questions we’re often asked about trees vs leach fields and septic systems.
What is a leach field?
A leach field, also known as a septic drain field or leach drain, is simply the area used by builders to dispose of wastewater from a home.
Together with a septic tank, a septic drain field, and all the piping associated with this equipment, a leach field forms an entire septic system.
Knowing what a leach field is and how it works can help you understand what (and what not) to plant in that area. The average leach field consists of perforated pipes resting in a bed of gravel about 15-18 inches deep, with all household drains leading first to a purifying tank and then to the leach field.
In most states, including Colorado, permitting agencies don’t conduct regular inspections of residential leach fields after they have been installed. Therefore, it’s important to plan ahead to avoid any potential issues with your septic system.
Why do trees grow in leach fields?
There are several reasons why trees end up growing in leach fields – and sadly, they tend to grow there remarkably well!
- Nutrient-Rich Soil – Leach field soil tends to be incredibly nutrient-dense. It might be unpleasant to think about, but the waste you’re pushing out from your home and into the septic area has large deposits of nutrients. There’s also oxygen in the drainage lines, which can encourage plant growth.
- Moist Soil – The soil in leach fields is moist, too. It remains consistently moist even during times of drought – as long as you’re still flushing toilets and performing other household chores that use water, the leach field is always getting water.
- Disturbed Soil – Finally, when leach fields are constructed, the soil is disturbed. This disruption loosens the soil and makes it lighter, airier, and all the more amenable to plant growth. It’s the perfect site for growing trees – if it weren’t for all the problems that tree roots cause, that is!
How do trees end up growing in leach fields?
So how do tree roots get in a septic drain field, to begin with? There are a few ways this can happen.
One is obvious – you planted them there. The takeaway of this entire article should be this – you should never plant trees near or in leach fields.
However, if you already have trees growing in your leach field (and you didn’t plant them there), you might be wondering how they got there.
- “Planted” by Animals – One is by animals burying seeds. Unfortunately, this is something you can’t control. Even if you fence in your leach field, small critters like birds and squirrels will inevitably make their way over there and deposit seeds, either by burying them or leaving them behind in their droppings.
- Carried by Wind – Even the wind can occasionally introduce new tree seeds to an area.
- Spread from Nearby Trees – Of course, you may have planted your tree a distance away from your leach field, assuming that the distance would keep roots out of your septic system. Unfortunately, trees can stretch their roots for long distances. And even those that are cut can still produce underground sprouts that morph into full-sized trees in locations farther away.
Can you plant trees near a leach field?
Here’s another question we are often asked – can you plant trees near a leach field?
Unfortunately, trees are opportunistic little buggers! Even if you haven’t planted trees directly over your septic area, they (or just their roots) can still wind up there.
Root systems, particularly those for large trees, can travel up to 20 feet in search of water. This varies depending on the tree species, but obviously, the further away from your leach field, the better. Keeping trees at least 50 feet away from septic systems is ideal, but if you plan on growing plants like willows, shoot for 100 feet.
Give your leach field a wide berth when planning out your landscape. Grasses, or even wildflowers, over your septic area make a better alternative.
Why are trees growing in leach fields a problem?
There are several key problems that can arise when trees start growing in leach fields. But the biggest problem that these plantings pose has to do with tree roots.
When trees send their roots down into the soil, it doesn’t take long for them to reach your septic system’s pipes. Some trees extend their roots up to seven feet into the soil, meaning it’s no problem for them to reach the perforated pipes of your leach field.
Once these roots reach the pipes, the real trouble starts. Most pipes used to build leach fields have lots of tiny holes, making it easy for roots to get inside. The pipes are usually composed of PVC plastic so it doesn’t take long for the pressure from the expanding roots to build and build – until the pipes burst open.
Even if they don’t get inside the pipes, the roots take up space in the gravel bed in which the pipes are situated. This is where all the filtered waste drains out so, as the pipes take up this space, blockages can occur.
Eventually, your tank will stop draining entirely – if the roots don’t cause your pipes to explode first, that is.
Can’t you just remove trees that are growing in a leach field?
Sure – but heavy sections of trees or heavy equipment on your leach field can lead to additional problems. Even driving a lightweight passenger car over a drain field can damage it, so it’s best to avoid planting anything in your leach field whenever possible.
As you can see, this can turn into an expensive and frustrating problem later on.
How much does it cost to have a leach field replaced?
When it comes to replacing or repairing each field, costs vary depending on the size, type of soil, and cost of local permits.
On average, you can expect to pay anywhere between $5,000 and $20,000 for this kind of project.
Areas with naturally sandy soil might allow for a cheaper project, but those with heavier soils will be more expensive. It’ll also be more expensive in areas that have trees, fencing, or other features that need to be removed first.
Should you remove tree stumps in leach fields?
If you have a tree stump in your leach field, it’s important to remove it. Certain types of trees can resprout from the stump.
Tree roots in septic drain field areas are obviously problematic – so they need to come out. However, this isn’t something you should tackle yourself. If you try to remove the stump yourself, you might destroy the leach field.
Instead, contact a tree care company to take care of the project for you. These professionals know the best ways to address trees growing in leach fields.
Can you leave smaller trees in a leach field?
If you’ve noticed trees growing in your leach field, you might feel tempted to just let sleeping dogs lie. After all, removing the stumps could potentially endanger your leach field even more, right?
That’s true, but you shouldn’t allow even small saplings to remain on your leach field. They’ll turn into mature trees, which will lead to even bigger problems (read – more expensive problems) over time.
Should you plant anything in a leach field?
To avoid tree roots in septic drain fields, there are a few simple steps you should take. The most obvious is to avoid planting these trees in the first place!
We get it. The leach field is a boring area of your yard, typically just a sprawl of bare space that you understandably want to fill with something else. You’ve got to take advantage of the soil and the space somehow – but it’s not a good idea to plant a tree there.
Fortunately, there are many other plants you can grow that will offer the same amount of beauty and visual appeal as trees – but without all of the costly headaches.
Ultimately, if you’re worried about the problem of tree roots in your septic system, you don’t have to be so paranoid that you avoid planting anything there entirely. Growing vegetation is actually a good idea since it can help prevent erosion and will also soak up some of the extra moisture that your drain field produces.
It’s also a great way to recycle nutrients!
The best alternatives will vary depending on the location and sun exposure of your leach field, as well as the climate where you live.
What to Plant in Leach Fields
Growing easy-to-care-for species like Colorado native grasses and wildflowers is always a good option for the leach field.
The soil here tends to be alkaline so you may want to consider plants that prefer a higher pH, like yarrow, coneflower plants, or even daylilies.
Perennials offer the same ease of maintenance as trees (you won’t have to replant every year). However, their roots won’t damage your septic system like tree roots will.
Annuals are good options, too, since their limited growing season means their roots will never grow long enough to interfere with your leach field.
Although herbaceous plants and perennials are better choices than trees, there are a few trees and shrubs that should be relatively safe to grow over a leach field, such as:
- cherry trees,
- Japanese maple trees,
- azaleas, and
- boxwood shrubs.
But keep in mind that herbaceous perennials and annuals will always be best – any plants that are woody are risky in septic fields.
Worst Plants for Leach Fields
If you absolutely must grow a tree or shrub, pick one that has notoriously shallow roots or roots that spread instead of diving deep, like blue spruce.
In any event, avoid these large, fast-growing trees. They can harm your septic tank faster than you can say, “Siri – call a plumber.”
- Pussy willow shrubs
- Japanese willow shrubs
- Aspen trees [link to LAM article on aspen tree alternatives)
- Birch trees
- Beech trees
- Elm trees
- Most maple trees (besides Japanese maple)
- Ash trees
- Tulip trees
Similarly, you should avoid growing vegetables or other edible crops since there’s no way to guarantee that crops grown over leach fields are safe to eat.
Need a Hand?
Worried about tree roots in septic drain field areas? Don’t panic – instead, give us a call. Here at LAM Tree Service, we have the expertise you need to deal with common tree problems like this.
We’ll work with you to come up with a solution to remove any trees growing in your leach field. Plus, we can give you some suggestions for what to plant instead. Contact us today for a consultation or give us a call at 303-674-8733. We can help you prevent expensive repairs to your leach field (and lots of headaches, too).
