Is a tree root killer the answer to your sewer pipe clog?

Calling a plumber can help you ID the best solution to your drain problem. (Photo by Kathy Oman)

Calling a plumber can help you ID the best solution to your drain problem. (Photo by Kathy Oman)

If you own an older home, there's a good chance you will eventually have to deal with tree roots invading your clay sewer pipes. This can be an especially common nuisance during periods of prolonged drought, since trees are searching for any source of moisture they can find, including water flowing through your sewer pipes.

One purported solution to this problem is pouring a chemical tree root killer down your toilet and letting it eradicate those roots for you. But, since we're talking about your home's main sewer lines - a potentially expensive and difficult repair or replacement project - let's take a moment to discuss this problem in more detail.

Confirming the problem

First of all, it's important to identify the cause of the drain clog before just assuming it's tree roots.

If you have access to the site plans for your home, determine where your main sewer line runs toward the street and see if there are any trees growing along that path. Of course, larger trees can have root systems that travel for many feet underground, so take that into consideration when surveying the area.

Also, try to determine if your sewer lines are clay. If your home was built prior to 1970, chances are good you have clay sewer lines. If not, there's a chance your lines are PVC, and tree roots will not be an issue. Of course, older homes may have had the lines replaced in the past, and some newer homes may have had clay lines installed despite PVC being the industry standard, so digging down to the pipe may be the only surefire way to find out that answer yourself.

If you do have clay pipes and you have trees within thirty feet of your main sewer line, there's a good chance your clog is caused by tree roots.

Using chemical tree root killer

Various chemical root killers are available from your local hardware or plumbing supply store, and all of them work on the same basic principle: the chemical is poured down a drain, most commonly the toilet, and the corrosive properties of the chemical kill the roots when it comes in contact with them in the drain pipe.

Since you are working with potentially dangerous chemicals, it's vital to read and follow the directions on the package you choose and abide by any safety precautions recommended. Not only may the chemical be harmful to your skin and eyes, it may also have potentially harmful environmental effects as well.

For example, in years past, copper sulfate was used extensively to free clogs and kill roots in drains. However this practice has been stopped because of the long-term corrosive effect this chemical has on your sewer pipes and the fact that it will kill beneficial bacteria in your septic tank, if applicable.

When you should call a professional

If there is any question in your mind as to whether or not tree roots are causing your clog, or whether a portion of your clay pipe may have collapsed due to the invasion of roots, you would be well served to contact a highly-recommended professional plumber to bring a borescope (a drain snake with a camera at the end) and determine what's causing the clog once and for all.

A professional plumber will also be able to offer some other solutions that may prove more effective with less potential hazard, such as trenchless sewer line replacement of a section of pipe that has collapsed or localized removal of the roots by means of a snake and cutting head.

Even more importantly, a professional can provide you with the peace of mind of knowing you're handling this repair as efficiently and effectively as possible, preventing another messy clog and protecting your single largest investment: your home.


If you had a clogged Sewer, the only way to know if you had tree roots in your sewer was to dig up the pipe and inspect it and see the cause of the blockage.The way most plumbers remove tree roots in a sewer pipe is by way of a "drain snake". The drain snake has a cutting blade on the tip and when the blade arrives to the root intrusion, it will cut and rip the roots from the sewer pipe.

Root killer was added to my toilet pipes. Will this effect the avocados on my tree. Are they safe to eat?

Consider using aluminum chloride AlCl3 this kills the roots and the tree will die starting from the roots. To protect the iron pipe you have to go through it with a 10 to 15 feet long pex flex pipe. Apply the aluminum solt immediately after treating the draining with a 100 ft long heavy dyty snake ( rent by home depot). Cuting the culprit first (the mature tree) it isn't quick solution. Killing the roots first it is better. In one year or so the tree will die. The first sign will be the bark popping up. You have two options. Dig all the draniage and replce with PVC pipe ($8000 to $15000), or get reed of the tree. If you choose the second option you will start from the roots of the tree. Finding aluminum salt it is a chalenge. I produced it by combining aluninum scrap with hydrocloride acid. To acelerate the reaction I used a battery charger. It is very danderous, the mixture starts boiling and you might hurt yoursel or go bling. I have a BS in chemistry. If you google then you might find AlCl3 or Al2(SO4)3 salt and buy it. You need at least 10 lb. salt to treat at least 5 times with 2lb. each treatment.

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