Killing roots with copper sulphate. What happens in drain/sewer pipe?
Q. I have huge amount of roots in the pipes. I'm looking for a source of copper sulphate but affordable. Here in Canada I buy it from Home Depot at cca 10 $ per kg (2 lbf cca). When I put the copper sulphate in the drain- I assume it will be distributed in the pipe but unfortunately only at the bottom of the pipe. I tried to speak with Iron Out people about this but was difficult to get an answer. When these blue granules are in the pipes, they stick to the cracks and they dissolve gradually but some of them will be flushed away? then the presence of the remaining ones will create a negative environment for the roots? I want to know what is happening there in the sewer pipe and also to find a source of copper sulphate for roots but cheaper- say at CCA 2 $ per Kg. Anybody knows?Please answer.Mike M
- London , Ontario, Canada
If you don't mind the pun, the Root of Your Problems lies, I think, in the sewer pipe connections ... which I'm guessing have concrete bell and (poorly fitting) spigot connections. Then the roots will search for water and seep in insidiously.
Solution ... replace with plastic piping, cemented construction ... or to clean/kill the roots, heck, you'd have to block off the end of the pipe and let the copper sulphate RESIDE inside the pipe for a day or so making sure, of course, that the pipe is nicely filled up.
- White Rock, British Columbia, Canada
A. Hi Mike. I see a 50-pound bag for about $2 to $2.50/pound on Amazon =>
Copper Sulphate 50 pounds
Q. I am a home owner who is having a problem with my septic tank. I was told that I could use copper sulfate in my tank to get rid of roots. Is this so? I have animals that would be close to the septic area, so would it be harmful to them? Does copper sulfate dissolve the tree roots? Would it dissolve any other type of clog that might be in the tank or field lines. Please help me.
home owner - Dyersburg, Tennessee
A. Copper sulphate doesn't exactly dissolve roots, Joan, it's a specific biocide that deters them and kills some other green things, mostly chokeweed and algae. Dead things eventually rot away, and I think that is what would happen. If the animals can't get to the septic tank I don't see any danger to them, and it isn't harmful to most green things.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Q. I was told to get copper sulfate, to treat my cactus garden' I bought some blue crystals but there no instructions on it. How and in what amount do I mix. I do not want to kill any cactus or any trees. Can you help me. we have a fungus and some root rot.Nancy Schrader
Hobbyist - Morgan, Texas
A. I found this information link [Oklahoma Co-operative Extension Service] on the web, it might help in understanding how Copper Sulfate works and how much to use.
- Salt Springs, Florida
Ed. note: Just exactly what was needed here, Chris. Thanks!
Q. I'm busting out some sidewalks due to roots growing underneath them and picking them up and cracking them. Now I hear that copper flashing would detour the roots away from the side walk. Is there any truth to that? Thanks.john rodgers
consumer - fort pierce, Florida
! Hi everyone.I was searching the internet for ways to solve the root problem in my sewerage system at home - and oh boy am I glad I eventually found a solution. For years I have now on a yearly basis had to have my plumbing cleared out at an expense of about 200 dollars per show! At each occasion I asked the plumber whether there was anything that I might pour in the drain to stop the roots from regrowing, and the resultant answer was always negative. Why should they slaughter the goose that lays the golden egg! They most probably knew about copper sulphate but was not letting a regular like me get away! In any case - thanks a lot for the advise. Regards, David.David Nel
private - cape town, South Africa
A. We had a lot of expense and problems with overflowing toilets requiring annual sewer cleanouts. One year we called a local RotoRooter franchise and after the $185 cleanout he sold us a product he said would help with the root problem. I think (this was a number of years ago) it was packaged under the RotorRooter name in a 1# canister with instructions on how to use it. The ingredient was copper sulfate. The bad news was it was $20. But it worked. We used it 6 months after the clean out and and twice yearly since and have not had to call a plumber for this problem since.
Later while visiting our county agricultural (farmers) co-op for gardening supplies I ran across copper sulfate on the shelf along with all the insecticides, fungicides, etc. One lb. canister was $9.95. We have used this twice yearly since and have not had any root problem with the sewer line. I know it does not fill up the line, but must seep into the cracks to kill roots entering there. Stands to reason the longer it is there, the better the penetration. So I use it at night before we go to bed so it won't just get washed away by the next flush.
It worked for us. Good luck.
- Birmingham, Alabama
May 17, 2008
A. The builder connected to old clay pipes when he ran my sewer lines. I just had my pipes done and all the roots he could get cut out. He has been my plumber for many years and he had recently found out about copper sulfate. He suggested that I use 1 1/2 cups of copper sulfate crystals every other day for 30 days and then once monthly after the first thirty days to keep from having to call and get this done again. He instructed me not to put it down any of my drains but directly in the cleanout outside my house just before bed and then flush to get it to the roots and leave in the pipes the maximum amount of time. I don't know if this will be helpful to anyone but this was not the intended use of what I bought and there were no instructions on the container. I did get it at the farmers co-op.Sherry Smith
- St. Louis, Missouri
November 25, 2008
A. RootX is not a copper sulfate product.
- North Royalton, Ohio
March 26, 2009
Q. Can anyone tell me what to use and how much to use to kill tree roots about 30 to 40' away from from my septic tank. There is a hybrid willow tree whose roots are taking over.Sherrie Pate
- Pelham, Tennessee
July 14, 2009
A. From 30-40 feet away the copper sulfate won't work. Adding it to your septic tank will kill any roots in the tank proper, but not the rest, that's why it's safe for the trees. Be aware that willow trees will spread their roots over 50 feet, several trees may be connected and the only way to get rid of the roots altogether is to kill the trees.
I had some invasive willow growing in my back yard and I was told the best way to kill willows is with products containing Dimethylamine salt (often seen as 2,4-D and sold as broad leaf weed killer like Spectricide weed stop.) It can also kill other trees and plants like roses, dandelions, and clover (but not grass) so you'll need to be careful about application. And yes, it works better than Glyphosate (Round Up or weed and grass killers) on willows, since it gets taken up by leaves and roots where Round Up gets taken up mostly by the leaves.
- Carson City, Nevada
August 15, 2009
Q. I understand that copper sulphate kills tree roots. I use Rid-x on a regular basis, to increase bacteria. Is there any detrimental effect to bacteria from use of copper sulphate? Thanks.Jo Coke
- Signal Mountain, Tennessee
June 28, 2010
Q. I've heard that drilling a 2-3" hole down about 8-10 feet over your sewer pipe and pouring copper sulphate down this hole once a year will discourage roots from even thinking about going near your pipes.
Drop a length of ABS or other plastic pipe into the hole and put a threaded cap on it to keep it open for next years application. (Cut it short enough so it doesn't interfere with your lawn mower.)
Sounds like good advice to me, but I can't for the life of me figure out how to drill this hole.
Haven't need able to find an auger the right size or a way to keep lengthening the drill.
I'm toying with the idea of using black threaded 1" pipe, so I can keep adding lengths to it, but what to use for a cutting head?
Also having trouble locating copper sulphate, everyone I ask advises against using it anyway for environmental reasons.
I can understand this if I was just flushing it down the toilet into the sewer system, but dispersing it into the soil ten feet down sounds like a fairly innocuous way to solve my problem.
I'd rather stop the roots BEFORE they get into the pipes than fight with them afterwards. (been there, done that, expensive)
I'd welcome suggestions.
- Burlington, Ontario, Canada
June 18, 2014
A. I have a suggestion for the guy that can't figure out "how to drill an 8 foot hole " in his backyard.
They can rent fencepost hole diggers!
Some are small, like a 2" auger.
I drilled a lot of holes with a 6" auger. There is an attachment that lets you go deeper, and get it stuck if it's clay.
Another way is to make a small one.
I do prospecting, so I needed a simple solution to drill thru the mud to find the rock bed.
parts: 1 large 2" or 2.5" washer,
1 steel rod 1/2" x 4'.
Now, using a hand held hack saw or other metal cutting device,
cut through washer. Inside diameter was either 1/2 or 3/4 in hole--got it cut--ok bend it down about almost 1/2".
Welder: arc works, you can braze weld it if you have the equipment, or pay a welding shop.
It takes less than a minute to zap a weld.
End product: one very simple post hole digger or pipe hole digger.
I used a steel rod i found. Some old car jack handles are 4' long...i used a 3/8 drill, and had to grind the shaft down.
It worked, but i should have had a bigger drill chuck. It ate mine, but i got my hole done!
(8' will wobble, use two 4' pieces); somehow make an attachment to extend the shaft. Some old jack turn handles have such a knuckle -- or have a nut welded on the up top end, and thread the extension.
Or dig down about 3 feet with shovel, and drill rest of way using a 5 or 6' rod. Then install 2.5"" steel fence post or pvc pipe. It's not actually part of the drain system so it could be steel pipe, fence post, 2 inch copper(expensive) or pvc.
Other part is a way to turn shaft: electric drill.
But if you opt to use a long car jack handle, don't cut the turnbuckle off!
You could use 1/2 in black pipe, weld on washer, drill in to ground and forget it!.
Note: new fence post are like this -- I think someone saw my idea. Neighborhood spies!!!
Available at most junkyards!
Or hire a fence guy to drill it for you!
I cant figure out why some of you guys can't figure it out!
Too much time in penny loafers and not construction boots, eh!
- new brunswick, Canada
Ed. note: "No good decision was ever made in a swivel chair" -- George Patton.
August 3, 2010
Q. Where are you Canadians finding the Copper Sulfate? What is the name of the product/brand it's sold under? I've search every hardware/farm supply store around and no one seems to have it except for one place had it in a 40-lb bag which is a lot more than I need.Patsy Barnhardt
- Chepstow Ontario
March 6, 2011
In Canada you can get the product at the pharmacy, you have to ask for it, it isn't on the shelf.
April 26, 2011
You can get large quantities at any agricultural store or grain elevator store site. Head down (or call first) any villages near where you live where they have such a store. The prices are much-much cheaper than the stuff you get in hardware store, but you will have to buy it in larger quantities.Navjot Sandhu
- Lansing, Michigan, USA
January 7, 2012
Try getting copper sulfate at a feed mill.Carl Fischer
- Leo, Indiana, USA
January 27, 2011
Q. My pipes go to a street sewer. How can I "hold in place" the Copper Sulphate to kill the tree Roots that are entering in the drain pipes? I just had Roto Rooter grind out the roots, as they did 3 years ago. Also, should the Copper Sulphate be washed into a sink or flushed in the toilet? and how much? Then would letting it sit overnight for many hours do the job?Bill Spencer
- Sonoma, California USA
February 1, 2011
A. Just had Mr Rooter channel the main line through two blockages. They also installed a cleanout between the tank and the main line. Have a 30+ year old system. My question concerns copper sulfate and clay pipe. Does the copper sulfate harm clay pipes? The installer explained about copper sulfate and we did pour some in the cleanout and flushed with water.Terri Martin
- Bulverde Texas USA
February 27, 2011
A. I have a house built in 1941. It has clay pipes with roots in them. For years we used plumbers' Drano, nearly all the other things mentioned here. about 3 years ago the toilet was backing up into the tub. we plunged used Drano etc. we are seniors and have limited money. We were in Publix grocery store and debating whether or not to call the plumber. I saw a product I'd never seen before. The name is Liquid Lightening. it is virgin sulphuric acid. We used it and it worked. We have not used any other product since. It is about $10 for 32 ounces. It does not say it dissolves roots but anything organic. It has always worked for us.alan jones
- jacksonville florida united states of america
February 28, 2011
! Hi, Alan.
Thanks for the success story. Be really careful with sulfuric acid -- it dissolves metal pipes as well as other stuff. And never even think about mixing it with any other drain cleaner. Most of the others are strong alkalines, and mixing a strong acid with a strong alkaline is explosively dangerous.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
June 27, 2011
! I just wanted to warn people that if they use Copper Sulfate in their drain field there is a chance that they could kill any trees that are close to the drain field.
I found this out the hard way. My sewer repair person recommended I put 5 pounds of copper sulfate in my drain field once or twice per month after he cleaned the roots out. After one application I now have a giant live oak that is completely dead. Another huge live oak that is looking very unhealthy and a smaller live oak that is showing signs of being sick.
I only gave my sewer system one application because before it was time for the second application my trees were starting to drop leaves and look sick.
Had my sewer repair person warned me that this may happen I would have opted to have the drain field mechanically cleared of roots whenever it needed it rather than have my beautiful oaks killed.
retired - Lakeland, Florida, USA
June 27, 2011
Hi, Gary. Thanks for the warning.
However, you might want to talk to your county agricultural extension service and see if someone can confirm this as the cause of the death of your trees. Some knowledgeable horticulturists and floriculturists are quoted in the previously referenced page at
as saying: "Use of this treatment has yet to cause the loss of a tree or shrub".
Ted Mooney, P.E. RET
Pine Beach, New Jersey
September 4, 2011
As a Chemical Engineer the Copper Sulphate can corrode Iron pipes too fast:
CuSO4.5H2O + Fe = FeSo4 + Cu
The pipe will be washed up by water as FeSo4 ...
- Milwaukee, Wisconsin, USA
March 5, 2012
I just purchased this product yesterday:
- Santa Fe, New Mexico USA
A. I would really question dumping large quantities of copper sulphate down the sewer. It is highly lethal..!! I would strongly advise checking with local authorities before doing it. This stuff can't be remove during the normal process of treating waste water. It could end up back in your drinking water.
Also...putting it in your septic system is just going to kill all the natural organisms and bacteria that have to be there for the septic system to work properly.
Really do your homework on this stuff before you use it.
- Whitby, Ontaio, Canada
June 27, 2012
Q. In a post dated July 14 2009 by M A Tullos- Carson City, Nevada an answer was given that copper sulfate will not be affective 30-40 feet out.
My question is: if one flows an large amount of water when applying the CuSO4 will it not be carried to the root site and do an adequate job?
I have a problem with roots approximately 60 feet out, I would appreciate an response and would like to know that this treatment will work.
- Linton, North Dakota, USA