Tree Roots in Drains: Signs, Fixes and Who Is Responsible

Tree roots get into drains through cracks, open joints and displaced pipes, drawn by the moisture inside. Once in, fine roots grow into dense mats that catch toilet paper, fat and debris, causing slow drains and repeat blockages. The lasting fix is to cut the roots out and then seal the pipe with a patch repair, a structural liner or a new section of pipe. Our drain repairs team does exactly that across Nottingham and the East Midlands.

This guide covers how roots get in, the signs, which trees cause most trouble, root cutting versus relining, and who is responsible when the tree belongs to a neighbour or the council.

How do tree roots get into drains?

Roots grow towards moisture, and a leaking drain gives off water, warmth and nutrients. They almost always enter through an existing weakness rather than breaking a sound pipe. Bristol Water's tree planting guidance adds that underground pipes are often cooler than the surrounding soil, so moisture condenses on them and encourages roots to grow close by, and that most of a tree's roots are usually within 600 mm of the surface.

Common entry points are:

• joints in older clay pipes, where the seal has failed or the pipe has shifted;
• hairline cracks from ground movement, frost or heavy loads;
• displaced joints, where one length has moved out of line with the next;
• pitch fibre pipes, used between the 1950s and 1970s, which can deform with age (see our guide to pitch fibre pipes);
• poor connections, such as a new branch cut into an old run.

Once a root is inside, it has water and shelter, so it keeps growing and thickening.

What are the signs of tree roots in drains?

Root problems build slowly, so the signs are usually a pattern rather than a single event:

• sinks, showers or toilets draining more slowly than they used to;
• blockages that come back weeks or months after being cleared;
• gurgling from plugholes or gullies;
• smells around outside drains or inspection chambers;
• a chamber that fills up when water is run upstream;
• damp patches, sinking paving or wet ground along the drain line;
• a large tree or hedge close to the route of your drains.

None of these proves roots are the cause. Our guide to the signs of a blocked or collapsed drain covers the other possibilities.

Which trees cause the most drain problems?

Large, thirsty trees planted close to old pipes cause the most trouble. Bristol Water's guidance, which draws on NHBC Standards Chapter 4.2, classes poplars, oaks and most willows as high water demand, and says poplar and willow should not be planted within 10 m of its pipelines. It lists ash, beech, elm, horse chestnut, lime, oak, sycamore, fruit trees and most conifers as trees to plant only at least 6 m clear.

These distances were written for water mains, so treat them as a guide for planting near drains rather than a rule. Where your garden is on clay, the soil adds to the risk, because Bristol Water notes that trees drying out shrinkable clay can amplify ground movement.

How is root ingress confirmed?

A CCTV drain survey is the reliable way to confirm roots. A camera travels along the pipe and records where the roots are, how much of the pipe they fill and which defect they came through. UK reports are usually coded to the WRc Manual of Sewer Condition Classification (MSCC5).

Our guide to CCTV drain survey reports explains the codes and grades in more detail.

Root cutting vs relining: which do you need?

You usually need both: cutting to clear the pipe, then relining or a repair to stop the roots coming back. Cutting is done with a root-cutting head on rods or high-pressure drain jetting equipment, followed by a camera pass to check the pipe is clear and show the defect.

Relining removes the joints roots exploit. Our guide to drain relining vs excavation compares the two, and drain relining explains our lining service.

Should you use a chemical root killer?

We don't recommend pouring herbicides or strong chemicals down drains. Whatever goes down a foul drain ends up in the sewer network, and from a surface water drain it can reach a soakaway or watercourse. Chemicals also won't seal the crack or joint the roots came through, so the problem returns. Never mix drain chemicals, as some combinations react dangerously.

Who is responsible for tree roots in drains?

Responsibility for the pipe follows the pipe, not the tree. You are responsible for a drain that serves only your property and sits within your boundary. Since 1 October 2011, pipes shared with neighbours and pipes beyond your boundary have been the water company's responsibility, according to Citizens Advice. Across Nottinghamshire and most of Derbyshire and Leicestershire, that is Severn Trent.

Whether a tree owner has to contribute to your repair is a question of nuisance law, not drainage rules. Talk to your neighbour first and share the survey. Gov.uk suggests trying to resolve neighbour disputes informally, then mediation, with court action as a last resort. Get legal advice before going further.

For council trees, Nottingham City Council's guide says it will address situations where its trees cause "actionable nuisances", that you cannot cut beyond your boundary without its written permission, and that you should take legal advice before any work on a council-owned tree. Other councils have their own tree teams.

Before cutting back or removing any tree, check whether it is protected. Trees under a tree preservation order, or in a conservation area, need the council's consent or notice before most work (gov.uk).

Does home insurance cover root damage?

Sometimes. The Financial Ombudsman Service says most buildings policies cover damage to underground pipes and drains you are responsible for, but insurers may reject claims as gradual damage or wear and tear, and many policies don't cover pitch fibre pipes. Our guide to whether home insurance covers drain damage explains more.

When to call a professional

Call a drainage engineer if a drain keeps blocking, runs slowly near a tree, or a survey has already shown roots. Repeated DIY rodding tends to push roots and debris further along without fixing the entry point.

We clear roots with jetting, confirm the cause with a CCTV survey from £149 + VAT, and seal the pipe with relining or a repair. Our drain repairs start from £250 + VAT, and lining, patch repairs and pipe replacement carry a 12-month guarantee. There is no call-out fee, and the price is agreed before work starts.

We work 7 days a week, 6am to 8pm, across Nottingham, Nottinghamshire, Derbyshire, Leicestershire and Lincolnshire. Book online or call 07300 600 950.

Sources

• Citizens Advice: who is responsible for repairing drains and sewers
• Bristol Water: a guide to tree planting near water mains (PDF)
• WRc: Manual of Sewer Condition Classification, 5th edition
• Nottingham City Council: common law rights over council-owned trees (PDF)
• gov.uk: tree preservation orders and trees in conservation areas
• gov.uk: resolving neighbour disputes
• Financial Ombudsman Service: underground pipes and buildings insurance