Are root killers an effective remedy for root-clogged sewer lines, drain lines, piping, drainfields?
Advice on dealing with root invasion of sewer piping, drain piping, septic tanks, and septic drainfields. This article describes approaches to removing and preventing root invasion and root clogging in sewer piping, septic piping, and septic drainfield pipes. At page top is a photo of roots growing into a clay sewer line connecting a Seattle WA building to the public sewer. Simply removing the roots or using a "root killer" won't fix a problem with recurrent clogging in a deteriorated or damaged sewer pipe.
This is part of our article series on sewer and septic installation, repair, maintenance and on planting trees, shrubs, or grasses or other plants on or near septic systems.
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Planting the wrong things or in the wrong places can lead to the need for expensive septic system repairs. Planting trees, shrubs, and even some ground covers over septic system components are causes of septic system failure in the drain field, leach field, seepage bed, or similar components. When roots invade a sewer line (shown below) or septic tank, seepage pit, cesspool, drywall or sewer and septic piping, including soakbeds or drainfields, the clogging problem can be expensive. Simply removing the roots by any means: mechanical using a drain auger or power snake, or more slowly by trying to kill the roots with chemicals, might temporarily improve wastewater or sewage flow but the problem is not fixed.
[Click to enlarge any image]
The photo at above left illustrates a modest root invasion at the joint in a clay sewer line at a property in Seattle, Washington. While roots continue to grow and occasionally slow or clog this pipe between a building and a city sewer, the underlying problem is an old, deteriorating clay sewer pipe whose joints are subject to heaving and breakage (photo above-right). Ultimately this line will need replacement. No amount of root killer, drain cleaner, or septic helper will repair a broken pipe.
See SEWER / SEPTIC PIPE CAMERAS for details.
Even where the sewer line or piping is not broken, just root-invaded through open joints, the most effective repair for root-clogging in drain or septic systems is by removing the root-invading plants themselves.
Tree, shrub or even some deep-rooting grasses and other plants will send out roots that find and are attracted by the nutrients in wastewater. Those roots find their way into the sewer or drain piping system through cracks in older pipes, particularly clay sewer piping or older cracking orangeburg pipe.
At clay sewer lines we often find roots invading the piping system at the hub joints that are not tightly sealed or at even older octagonal clay pipe sewer lines that had no water-tight connectors in the first place. Sewage effluent seeps out into the soil around these pipe openings that in turn invite roots to enter, grow, and even increase the damage to the pipes. Such root invasion is often undiscovered until building occupants begin to notice slow drains or worse, a sewage backup into the structure.
To repair root-invaded sewer piping, there are these approaches:
We advise against using chemicals or caustics to "kill" tree or other plant roots which may be present in or near septic system components. People fearing that roots will clog or have already clogged their septic system piping, particularly drainfield piping, are tempted to buy these products. This is another example of a "magic bullet" that does not work, is dangerous, contaminates the environment, and is illegal in some jurisdictions.
Root killers as environmental pollutants: OPINION: First, using a chemical to kill or to "prevent" invasion of roots in septic piping means you are pouring toxic chemicals and contaminants into the ground water - into the environment, and possibly right into your own or someone else's well and drinking water. This is a bad idea and is prohibited in many communities.
Root killers as a magic bullet to repair a septic system: OPINION: Second, if septic drainfield or other pipes are already clogged or partly clogged with tree or other plant roots, even if you killed the roots in the pipe you're leaving the clogging material.
If piping in a septic system has become root-clogged, it is often the case that not only are the pipes clogged, they may be dislocated or even broken by the growing tree roots. You may find you've contaminated the environment, left the clog in place, and wasted your money since you'll still end up digging up the clogged line to replace it. [The photograph above is a simulation of pouring a chemical into the septic system through a toilet. Don't do this.]
Planting trees, shrubs, and even some ground covers over septic system components are causes of septic system failure in the drain field, leach field, seepage bed, or similar components. Planting fruit trees, or vegetables (or anything else edible) over the septic drainfield might produce food that is unsafe to eat:
see SEWAGE CONTAMINANTS in FRUIT / VEGETABLES for details.
Continue reading at PLANTS & TREES OVER SEPTIC SYSTEMS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
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I have two septic tanks, the first seperates solids from liquid then sends the liquid to the second tank which has a septic pump that pumps the liquid UP to a drain field.
I want to kill brush over the drain field . The drain field is 1100 ft ABOVE my well . Is there a LIQUID root killer that I can use in this septic system as the copper pellets will never get up to the drain field and will sit in my seperator tank .
Can the copper pellets be ground into a powder - the powder mixed into a slurry that will be pumped to my drain field ? - email@example.com
We don't recommend chemicals and treatments in septic systems - search InspectAPedia for
"Septic System Additives & Treatments" for details.
Basically most such treatments are limited in effectiveness, risk damaging the environment, and are illegal in many areas.
If your drainfield piping is being invaded by roots we have found that even if you temporarily kill off roots in the piping they return in a year or two and repeat a costly clog. The solution is to either remove plants or excavate and install root passage barriers around the drainfield.
Take a look at PLANTS & TREES OVER SEPTIC SYSTEMS for details about planting over or near septic system components, and see ROOT KILLERS in SEWER LINES or SEPTIC PIPES for our advice on the use of root killers in septic system tanks and drainfields.
Also see SEPTIC TREATMENTS & CHEMICALS for our explanation of the risks of using chemicals and other treatments in septic systems.
What safe treatment is there for redwood tree roots...can I treat the end of root(s) I've exposed with something safe for aerobic bacteria in leach field? Can I 'paint' the end of the large root with something effective to kill only that root? Thanks. - Nanette
Nanette, my OPINION is that if you have large trees close to a septic drainfield their roots will continue to invade the field. If you kill off an individual tree root by cutting it back, the tree will send out new roots in its place. If you kill off enough roots to keep the tree out of the drainfield you'll likely kill the whole tree - a hazard of a different sort.
Those tree roots are pretty smart - good at seeking out water and the nutrients in septic effluent.
Thanks for your opinion. My redwood trees are 50 ft. away, but one of those roots has somehow navigated upward, I have it 'confined' in a 3" abs pipe, so I could 'treat it individually, if I knew what to do/what product to buy. The leach field is protected both upward and downward by cement-block retaining walls. It has lasted for 30 yr. until this year's 'root clog'. I have dug up the leach field, cleaned the rocks, replaced the drain pipe system which is a gravity system, but now with 'vertical inspection ports', as well as a 'cleanout'/drop for root treatment separate from cement septic tank. I just need to know how to treat this one invasive root. SIGH. What can I pour into the pipe containing the root to kill just this one invasive root, safe for the San Lorenzo River 60 ft. away?
Nanette: impressive that those trees sent out a 50 foot root. Look there are "root killer" products sold to dump into septic systems to try to kill off tree roots. They have the down side of leaving dead roots in the system, no permanent solution to the problem, and in at least some cases, contaminating the environment. With the river less than 100 feet from your septic system I'd prefer not to use chemicals.
If you've got just one bad boy tree root that wandered 50 feet from the tree and into your septic, I'd try to follow the root back 20 feet or more from the septic system and cut it off there.
I agree that I don't want to use chemicals, either, i.e., copper sulfate, etc.
However, trying to 'follow that redwood root back' is not trivial in my situation, as the root has grown 'upward' about 8-10 ft. above the ground level of the tree, and removing that depth of material is not as, ha,ha, as smart as the tree is.
I was hoping for something like say, rock salt solution, confined to that root...is there no 'solution-solution', forgive me, for both the tree health (one root will not kill a redwood tree (coppice category), I am pretty sure it is not the 'tap root') and life-cycle leach field maintenance cost?
Thanks for your time in this discussion. Surely their is an environmentally harmonious way to solve this.
I am currently looking for information on 'root deterrents', which seem to be a better avenue of research than 'root killers.' So far, it seems that salt may be the 'solution'. Let me know if you have any further suggestions re environmentally conscious root deterrents than only the 'physical digging down 10 ft.' unusable suggestion in my case.
In short, dumping salt or chemicals into the soil is not a recommended practice, and as I warned earlier, it's illegal in some jurisdictions. The risk is that you contaminate a well, groundwater, or other surface and subsurface waters, not to mention that root killers and root deterrent chemicals are a short-lived band-aid for a problem of roots invading septic systems.
The solutions that work are to clear out pipes, cut back roots, or where practical, remove trees or plants that are invading septics - not so practical in your case where you have large distant trees.
Even more costly are "solutions" that move the septic fields or attempt to insert buried barriers.
Last, research by septic experts such as Minnis and Gayman confirm that putting any significant levels extra salt directly into the drainfield or sending it there via a septic tank or building piping is a quick way to destroy the drainfield. I'd be concerned about putting enough salt in or around a drainfield to kill or retard root growth since it is risking if not plain asking for very expensive drainfield damage as well.
I do not disagree nor not care for the advice given, but am looking for a long-term solution to my problem.
As my drainfield lasted 30 yr., instead of the usual 10 yr, until 'large root impacted', and, as I have cut that root back 7 ft. and 'confined it' in a 3" diameter abs pipe, one cannot say that I have solved the problem by ignoring your advice....I AM sensitive to my forest and my river, which is how we got involved in our discussion in the first place.
What we seem to agree on is that only physical 'confinement'/'redirection' of the root is the best ecological solution. Hmmm...
what I HAVE done, is improve my leach field by removing/cleaning the rocks, replacing the leach line pipe including new 'vertical inspection ports', and cleanout, such that, perhaps, 'mechanical' removal of any invasive roots can be handled by annual inspection and 'mechanical removal'by 'snake' cutting before impaction.
I appreciate the input from you that mechanical options are preferred to chemical options.
Some mechanical approaches to avoiding use of chemicals to attack invading tree roots are in the next Q&A.
I had an elm tree near the tank and when the tank was pumped we saw the roots had penetrated the tank. We cut down the tree but it keeps coming back, which I assume means the roots are still alive and may continue to grow into the tank. Any suggestions on keeping the roots from finishing off the tank? I didn't plant the tree; it was there when I bought the place. Thanks, Cole
Cole, persistent tree roots around septic components are indeed an annoying problem. Quite a few readers ask about using root killers. Our OPINION is that there is a risk of contaminating the environiment, such products (and all septic treatments) are actually illegal in many jurisdictions, and worse, years ago when we tried the most popular products we found that the root killer was not a long lasting repair - two years after de-clogging by removing roots from an invaded pipe and using root killer we had to clear the pipe again.
Other than manually digging out all of the invading root systems (and the stump) near your septic tank, you can reduce root invasion by making the septic system less attractive to and harder to invade by tree and other plant roots:
(Apr 13, 2014) Anonymous said:
My neighbor has several large elm trees that are already invading my septic system and tank. They are just the other side of the fence and only a few feet from my tank and drainfield. I have no legal recourse to make him remove the trees. I've been pouring copper sulfate down the toilet and into the tank and this works for awhile but of course they just grow back. I am a single Mom with very tight finances and I don't have the money to replace the tank or to pay the many thousands to remove the huge trees.
The roots may even be growing into the foundation of my home and up into my sump pump. I was wondering if I could pour the copper sulfate right along the fence line to stop the roots from coming into my property. I am really desperate here and I don't know what else to do. I have called the city, an attorney, the health dept., etc. The trees may have grown wild so I don't have any legal options. I have to talked to the neighbor and they said they would take them down but I think they found out that it would cost thousands to take them all down as they are very tall and very close to my home, their garage and power lines. I don't know what else to do to stop these roots from coming into my property. Old ordinances allowed the fence line very close to my home and tank system.
Anon, you already know my view of using root killers in septic fields from the article above. Your note seems to confirm that the chemical doesn't solve the septic problem you describe and I add that you're at risk of killing the bacteria needed for the septic tank and drainfield to function properly. The result of that is a ruined drainfield and contamination of the environment around and in your property with sewage pathogens - none of which sound very appealing.
Even cutting down the trees won't remove the roots nor cause the roots that have already grown into your system to disappear.
Other readers have tried constructing an underground barrier to root movement: a step that's costly an possibly ineffective - roots will seek out the nutrients in sewage effluent.
A combination of tree removal AND root removal AND stump killing might work.
Questions & answers or comments about the use of root killer treatments to control trees, shrubs, or other plants whose roots invade the septic system piping or leachfield (soakaway bed).
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