Short answer
Tree roots can grow into sewer pipes through joints and cracks, because the pipe carries water and nutrients that roots are drawn to. Once inside they can slow flow, catch debris and eventually cause blockages or pipe damage. Roots can be cleared mechanically or with high-pressure water, but if the pipe is damaged they tend to return, so a repair or replacement may be needed. Costs vary widely, and insurance coverage depends on your specific policy.
How roots get into sewer pipes
Healthy pipes are generally sealed. Roots most often enter older pipes with loose joints, clay or concrete sections, or pipes that have cracked or shifted. Fine roots slip into tiny openings, then thicken as they find a steady supply of moisture. Over time they can form a dense mass that traps paper and waste.
Newer plastic pipes with tight joints are generally less vulnerable, though no pipe is entirely immune if damaged.
Signs of roots in a sewer line
- Several drains running slowly at the same time
- Gurgling from toilets or drains
- Repeated backups in the lowest drain in the house
- Sewage smell indoors or in the yard
- Unusually lush or green strips of lawn, or soft wet patches, along the pipe route
- A dip or sinkhole in the ground in more serious cases
These signs can have other causes, such as grease, flushed items or pipe collapse. A camera inspection is the most reliable way to see what is actually in the pipe.
How serious are roots in a sewer line?
It depends on how far the problem has progressed. A few fine roots can be an early warning. A heavy blockage can cause sewage to back up into the house, which is a sanitation concern and can lead to costly cleanup. Left unaddressed, roots can also widen cracks and contribute to pipe failure. Acting early is generally cheaper than waiting for a backup.
How roots are removed
Camera inspection first
A plumber feeds a small camera through the line to locate roots, assess the pipe’s condition and decide on a method.
Mechanical cutting
A powered cable fitted with cutting blades clears the root mass. It is common and effective for restoring flow, but roots usually regrow.
Hydro jetting
High-pressure water scours roots and buildup from the pipe wall. It can clean more thoroughly than cabling, though it may not suit very fragile pipes, so a professional should judge this.
Chemical treatments
Foaming root killers are sold for homeowners. They may slow regrowth in the short term but do not fix the opening that let the roots in. Follow label directions carefully. Some products can harm plants, and some are not suitable for septic systems, so check before use.
What dissolves tree roots in sewer lines?
Commercial root-killing products are designed to kill roots inside the pipe so they can be flushed out. Home remedies often suggested online, such as rock salt, lack strong evidence and can be harmful to the pipe system or the environment. If a blockage is already causing backups, a plumber is usually the safer route.
Repair, relining or replacement
If the camera shows damaged pipe, clearing roots alone is typically a temporary fix. Options include:
- Spot repair of a short damaged section
- Pipe lining, where a resin liner is cured inside the existing pipe to seal joints and cracks, with limited digging
- Pipe replacement, either by trenching or by trenchless methods such as pipe bursting
The right choice depends on pipe material, the extent of damage and access. Get more than one quote when the work is major.
How much does it cost?
Prices vary by region, access, pipe depth and the method used. Clearing a line is generally much cheaper than replacing it, and a full replacement can be a major expense. Because quotes differ so much, ask for a written estimate that states the method and whether a camera inspection is included. We avoid quoting specific figures because they change by location and over time.
Does insurance cover tree roots in sewer lines?
It depends on the policy and who owns the pipe. Many standard homeowner policies may not cover wear-related damage or routine root clearing, but some may cover sudden, accidental damage or resulting water damage inside the house. Responsibility for the section of pipe under the street or at the property boundary often belongs to the utility or local authority, while the pipe on your property is usually yours. Some insurers and utilities sell optional service line coverage. Read your policy and talk to your insurer before work begins, and keep photos and inspection reports.
Preventing root problems
- Know where your sewer line runs before planting.
- Keep large, thirsty trees well away from it. Fast growers such as poplars and willows are commonly named as problem species; see our look at hybrid poplar roots. The wet-site picks in trees for waterlogged and wet soil flag which species to keep away from pipes.
- Choose smaller trees for areas near pipes, such as those in our guide to small trees with shallow, non-invasive roots.
- Fix leaking pipes and dripping fixtures, which attract roots.
- Schedule periodic inspections if your pipes are old and mature trees are nearby.
Roots can affect more than drains. Our pillar article on whether tree roots can damage your foundation covers the other main concerns near a house.
FAQ
Can I remove the tree to solve it?
Removing the tree stops new growth from that tree, but the pipe damage stays and roots left in the pipe need clearing. Ask a plumber and an arborist.
Will roots grow back?
Often yes, unless the pipe is sealed or replaced.
When should I call a professional?
If you have repeated backups, sewage smells, or several slow drains, call a plumber rather than relying on chemicals alone.