Chemical root killer is a specialized treatment designed to address tree and shrub roots infiltrating and clogging residential plumbing lines. This product can be used reactively to eliminate existing root masses or preventatively to inhibit new root growth within the sewer pipe. Proper application ensures the chemical effectively clears the line while maintaining plumbing system safety and minimizing environmental risk.
Identifying the Need and Choosing the Product
Root killer should be used when symptoms indicate a developing sewer line obstruction. Common signs of root intrusion include slower drainage across multiple fixtures and gurgling noises from toilets or drains. More serious indicators are sewage backing up into the lowest drain or unusually lush, green patches of grass, suggesting a pipe leak is feeding the roots. Root killer is most effective as a maintenance tool, especially after the line has been mechanically cleaned (snaking or hydro-jetting) to remove the bulk of the root mass.
When selecting a product, you typically choose between two main active ingredients: copper sulfate and dichlobenil. Copper sulfate is a traditional granular or crystal product that kills roots it contacts directly by releasing copper ions. It primarily targets roots growing along the bottom of the pipe where water flows. Dichlobenil, often formulated as a foam, works as a growth inhibitor and contact herbicide. The foaming action allows the chemical to expand and coat the entire interior circumference of the pipe, treating roots that grow higher up in the line.
Step-by-Step Application Guide
Preparation is necessary for both safety and effectiveness before application. Always put on protective gear, including chemical-resistant gloves and safety goggles, to prevent skin and eye exposure. Locate the correct access point, typically the main sewer cleanout closest to the house. If a cleanout is unavailable, use the toilet nearest the main sewer line. The goal is to introduce the chemical as close as possible to the pipe section requiring treatment.
If using a granular or crystal product like copper sulfate, measure the amount specified by the manufacturer, often one to two pounds for a full treatment. If applying through a toilet, pour the measured amount into the bowl in small increments (e.g., a half-pound at a time) to prevent clogs. Flush the toilet after each increment to ensure the crystals are carried down the drain line. For foaming products, the entire container is typically poured into the toilet bowl.
Ensuring the chemical reaches the roots and remains in contact long enough to work is important. For both granular and foam treatments, follow the initial application with a specific amount of water, usually two to three gallons, to push the chemical to the obstruction point. This is accomplished by holding the toilet handle down during the first flush to maximize water volume or by flushing twice.
After application, the chemical needs time to work, so avoid using any water for a specific duration. This “rest period” is typically six to twelve hours, making application just before bed recommended. This timing allows the chemical to sit undisturbed and maximize contact with the root mass. For preventative maintenance, repeat the application every six months, ideally in the spring and fall when root growth is most active.
System-Specific Considerations and Safety
The type of plumbing system is an important factor when selecting and applying root killer. If your home uses a septic system, exercise caution, as certain chemicals can disrupt biological processes. High concentrations of copper sulfate can temporarily reduce the population of beneficial bacteria in the septic tank responsible for breaking down solid waste. While bacterial activity usually returns to normal within about two weeks, choosing septic-specific formulations is safer.
Foaming root killers containing dichlobenil are often the preferred option for septic systems because they pose a lower risk to the tank’s bacterial balance. The chemical targets the roots without negatively impacting the septic system’s function. If your home is connected to a municipal sewer system, standard root killers are generally acceptable. However, check with your local water authority, as some municipalities prohibit the use of certain chemicals.
Regardless of the chemical used, proper handling and storage are important for user safety. Always read and follow the manufacturer’s instructions, as the products contain herbicides and other chemicals. Store all root killer products in a secure location away from children and pets. If a complete line blockage prevents the chemical from flowing out and causes sewage to back up into the home, stop using all water immediately and contact a plumbing professional.