Tree Roots in Drains: Signs, Causes and Fixes

Tree roots get into drains through cracks, open joints and damaged sections of pipe, 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, usually with a patch repair, a structural liner or a new section of pipe.

This guide explains how roots get in, the signs to look for, how a camera survey confirms the problem, and what a proper repair involves.

How do tree roots get into drains?

Roots grow towards moisture, and a leaking drain gives off both water and nutrients. In most cases they enter through an existing weakness rather than breaking a sound pipe. Checkatrade lists tree root ingress alongside freezing and age-related wear as common causes of drain problems, and Rentokil points to cracked old clay pipes as a typical weak spot.

Common entry points include:

• joints in older clay pipes, where the seal has degraded or the pipe has shifted;
• hairline cracks caused by ground movement, frost or heavy loads;
• displaced joints, where one pipe has moved out of line with the next;
• pitch fibre pipes, which were popular between the 1950s and 1970s and can deform and blister with age;
• poorly made connections, such as a new branch added to an old run.

Once a root is inside, it has water and shelter, so it keeps growing. The mass thickens over time, which can widen the gap and make the damage worse.

What are the signs of roots in your drain?

Root problems usually build slowly. Watch for:

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

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

How is root ingress confirmed?

A CCTV drain survey is the reliable way to confirm roots. A small camera travels along the pipe and records exactly where the roots are, how much of the pipe they fill and what defect they came through.

Survey reports in the UK are usually coded to the WRc Manual of Sewer Condition Classification (MSCC5). Each observation records the distance along the pipe, a defect code, its size and its clock position. For roots, you are likely to see:

Roots are recorded as a percentage of the pipe's cross-section, so you can see how severe the obstruction is. Our guide to CCTV drain survey reports explains the codes and grades in more detail.

How are roots removed from a drain?

Roots are removed mechanically. Drainage engineers use cutting heads on rodding or high-pressure drain jetting equipment to cut through the root mass, then jet the pipe to flush out the debris. A follow-up camera pass checks the pipe is clear and shows the defect the roots grew through.

Cutting restores flow, but on its own it is a temporary fix. The roots are still alive outside the pipe, and if the crack or joint stays open they will grow back. How quickly that happens varies from site to site.

How do you stop tree roots coming back?

Once the pipe is clear, the entry point needs sealing. The right repair depends on the survey:

Relining creates a new, jointless pipe inside the old one, which removes the gaps roots exploit. Our drain relining vs excavation guide compares the two approaches. Our repairs, including lining, patching and pipe replacement, carry a 12-month guarantee.

Should you use a chemical root killer?

We don't recommend pouring herbicides or other strong chemicals down your drains. Anything you put down a drain ends up in the sewer network or, from a surface-water drain, in 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. If roots are the issue, ask a drainage professional about mechanical removal and repair.

Whose tree is it, and who pays?

Responsibility follows the pipe, not the tree. In England, you are responsible for drains that serve only your property and sit within your boundary. Since 1 October 2011, pipes shared with neighbours and pipes beyond your boundary have been the water company's responsibility (Citizens Advice). If roots are in a shared or public pipe, report it to the water company, which is Severn Trent across Nottinghamshire and most of Derbyshire and Leicestershire.

If a neighbour's tree is involved, talk to them early and share the survey findings. For your own drains, check your buildings insurance. The Financial Ombudsman Service says most policies cover damage to underground pipes and drains, but gradual damage and wear and tear are common exclusions. Our guide to whether home insurance covers drain damage explains more.

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

How can you prevent root problems?

• Find out where your drains run before planting, and keep large, thirsty trees away from them.
• Deal with small defects early; a single patch repair costs far less than a collapsed pipe.
• If you have mature trees near a drain, consider a periodic camera check or maintenance jetting.
• Keep fats, wipes and debris out of the drain, so small root intrusions don't turn into blockages.

When to call a professional

Call us if a drain keeps blocking, runs slowly near a tree, or a survey has already shown roots. We clear roots with high-pressure drain jetting, confirm the cause with a CCTV survey (from £120 + VAT, including a written report), and seal the pipe with drain relining or a repair. There is no call-out fee, and the price is agreed before work starts.

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

Sources

• Checkatrade: Signs of blocked drains
• Rentokil: Brown rats in sewers and drains
• WRc: Manual of Sewer Condition Classification, 5th edition
• Citizens Advice: Who is responsible for repairing drains and sewers
• Severn Trent: Sewer pipe responsibility
• Financial Ombudsman Service: Home insurance
• gov.uk: Tree preservation orders and trees in conservation areas