Ask Your Question

Angie's List Answers is the trusted spot to ask home improvement and health questions and get answers from service companies, health providers and consumers. For ratings and reviews on companies in your area, search Angie's List.

Top 30 Days Experts
Rank Leader Points*
1 kstreett 240
2 Guest_9020487 110
3 Guest_9190926 105
4 GoldenKid 100
5 ahowell 95
6 KnowledgeBase 95
7 skbloom 80
8 Guest_98024861 70
9 Guest_9311297 70
10 Guest_9400529 70

*Updates every 4 hours

Browse Projects By Category

Question DetailsAsked on 6/21/2014

Is copper sulfate safe to use to kill tree roots in water line

Tree roots are growing in my lateral sewer line from the house out to the main sewer line. Can it eat through the pipes as well as destroying the tree roots.

Do you have the same question? Follow this Question

1 Answer


Illegal to discharge directly into sewer system in many areas (public sewer) - plus it dilutes quickly with sewer use, though does work well in septic systems where allowed, to kill roots growing into the leach field. It works great as a preventative in the backfill immediately around pipes, but there are better products for using in sewers - ones that are regulated and approved for such use. Also, the commercial products like Root-X have components in them that make it adhere to the roots so it actually has time to act rather than just washing on past, the dichlor or similar herbicides not only kill roots but prevent growth for 6-12 months. The commercial foaming products also disperse it all around the pipe wall, whereas washing copper sulfate in just stays in the wetted zone at the bottom of the pipe unless pretty well plugged, as well as having degreasers that help cut the grease buildup off the pipe walls. Root-X, for example, runs about $15/lb versus about $3-5/lb for copper sulfate, but pound for pound works much better so you only need 2-4 lbs versus the 10-20 pounds commonly used with copper sulfate.

Also - copper sulfate is corrosive, particularly to metal pipes.

Be careful if using foaming type - bottom level (basement/ground floor) floor drains and anu other untrapped open pipe have to be plugged with expanding rubber plugs (about $5 each) so it does not foam up out of the drain onto the floor. Ditto to plug or clamped rubber cap or threaded cap on cleanouts. Can also come out of basement washtubs and tubs and showers and such - so put a stopper in them and fill with a few inches of water to prevent filling with nasty foam. I have never heard of it coming up beyond downstairs toilet or basin traps. Also, use only downstream (like in cleanout) if you have a sewage lift/grinder pump, and keep a trickle of water running from the house into the sewage lift pump so it cannot back up into the pump and damage it.

Have not had to use it so have not read instructions for awhile, but if not contrary to instructions I would use twice a month apart for the immediate existing root kill, then every 6-24 months depending on how fast your roots grew into your pipe, based on past root blockage and routing intervals.

There are li9nks to a couple of other questions and responses on same basic issue below this response, too.

Answered 5 years ago by LCD

Related Questions

Terms Of Use
Privacy Policy