Why Do Plumbers Say Pour Rock Salt Down Your Toilet?

Modern plumbing is certainly preferable to the methods our ancestors used, but having a system of pipes leading into your home does present its own set of problems. Plumbers sometimes recommend pouring rock salt down your toilet as a solution to a common pipe problem.

Sometimes, you might notice your drains are emptying slowly, detect strange odors from your drains or hear a gurgling sound from your toilet. These are all signs that tree roots may have grown into your pipes. Pouring rock salt down your toilet is one of the remedies that pros often suggest for getting rid of those pesky roots.

Having tree roots infiltrate your pipes is a quite common issue for homeowners. Roots are attracted to water sources and will grow toward them, so any small crack or break in a sewer pipe under your home can allow tree roots to enter. Once they're in, those roots — now having found a steady water source and nutrients — will continue to grow and may eventually fill the pipe completely.

This blockage will naturally cause problems in your bathroom and kitchen, and your pipes will become more damaged over time. If you don't catch and solve the problem quickly, you may eventually need to replace your entire sewer line, and that's naturally a big and expensive project.

This is where rock salt comes in. Made of sodium chloride, rock salt pellets will destroy tree roots on contact. Flushing rock salt down your toilet will move the salt to wherever the tree roots have invaded, quickly killing them so they can't continue to advance further into your pipes. Plumbers sometimes recommend this as a quick, DIY way to remedy clogs — but it's not a perfect solution.

One problem with pouring rock salt down your toilet is that the salt crystals could actually add to the blockage. As an alternative to using rock salt pellets, one option is to melt the rock salt in water and pour that solution down the toilet. In liquid form, however, the rock salt will just wash over the roots and may not sustain enough contact to actually kill them.

In any case, killing the roots so they don't continue to grow only stops the problem with your clogged pipes from getting worse. Using rock salt won't completely expel the roots from the pipes, so they'll continue to block water flow. There's also the risk that the rock salt will kill the roots of healthy plants in your yard. Plus, you haven't dealt with the original issue: a crack or break in your pipes.

Foaming root killers are one readily available alternative to rock salt. (Or, experiment with homemade root killers if you're nervous about pouring chemicals into your drains.) Because they create a foam that fills the pipe, the chemicals in these products stay in contact with the roots long enough to kill them.

But ultimately, nothing that you flush down your toilet will be a permanent solution for roots in your sewer line. If you use rock salt or foaming root killer in a pinch, follow up with a call to a plumber.