How roots get into drains
Roots grow towards water and nutrients, and a drain gives them both. A drain gives them both. They enter through cracks, loose joints and worn seals.
Once inside, the roots grow thicker and form a mat. The mat catches paper, fat and other waste. As a result, the drain slows and can block fully.
Which trees are most problematic?
Fast-growing trees with wide roots cause the most trouble, because they seek water far away. Willows, poplars and some others are well known for it. Even small shrubs can cause problems if they sit close to a weak joint.
Distance matters, yet no tree is always safe or always harmful. Because the real risk is a faulty joint, a sound pipe may stay clear for years.
Diagnosing root ingress
Signs include slow drains, gurgling and repeat blockages. A camera survey shows roots inside the pipe. It also shows where they enter.
Without a survey, you may clear roots again and again. Therefore, ask for footage before you agree to repairs.
Treatment options
Roots can be cut out with special tools or washed out with a high-pressure water jet. This clears the pipe, but roots often grow back. The joint stays open until you repair it.
For a lasting fix, repair or reline the pipe so the gap is sealed. Our guide to drain relining explains how. Some cases need a section replaced.
Which treatment to choose
Choose by the pipe’s condition, since that decides what can work. If the pipe is sound apart from a few gaps, relining may work well. If it is broken, replace it.
Ask for the options in writing. Cutting alone is cheaper at first, but regular visits can add up. A repair may cost less over time.
Preventing root ingress in new drainage
Modern pipes use sealed joints that roots find harder to enter, since the gaps are tight. Plan planting away from drain runs. Ask your builder to use good materials.
Keep records of where drains run. This helps you choose planting sites, because you know what lies underground.
When the problem is your neighbour’s tree
Roots may come from a tree on neighbouring land, so the cause may not be yours. Talk to your neighbour calmly first. Share the survey report to show the cause.
Check whether the tree has a tree preservation order, since cutting roots of a protected tree needs consent from the council. Take advice before you cut anything, because disputes can be costly.
Related guides and local help
If you want to know more, read Blocked Drain Clearance Cost Guide: What Affects the Price. You can also read 7 Things You Should Never Flush Down a Toilet in the UK and Chemical vs Mechanical Drain Unblocking: Which Works Best?, because they cover closely related problems.
These guides help too: 10 Signs Your Drain Needs a Professional, Not Just a Plunger, CCTV Drain Survey Cost Guide: What Affects the Price, Shower Not Draining: What You Need to Know to Fix It, Drain Camera Inspection: What to Expect and How to Read It and Sewer Smell in the House: Causes and How to Fix Each One. Each one explains a related topic in plain English.
Need help near you? Read our blocked drain guide first, or see Blocked Drains in Stockport and Blocked Drains in Exeter. You can also see Blocked Toilets in Bracknell, since every service page has a free quote form. We pass each request to a local drainage engineer.
