Septic tank tree root problems

How tree roots damage a septic tank and its pipework, whether it can be repaired, and when insurance helps.

Sam WarrenUKDP co-founder
Published4 May 2020
Updated26 Oct 2026
Read time4 min

Key takeaways

Tree roots can break through septic tank walls or pipework, letting groundwater into the tank or blocking the pipes.
You'll usually only learn of root problems if you see roots through a manhole or someone, such as the tanker operative, spots them.
Root damage to the tank itself is hard to repair, and in many cases the tank needs replacing.
Get a second opinion on any offered tank repair, as nobody can guarantee how long it lasts and it may void the warranty.
Roots in the pipework from the house can sometimes be cut out and the pipe repaired, at lower cost and with less disruption.
Most buildings insurance policies cover tree root damage to septic tanks and their pipework, so check your policy.

Is your septic tank having tree root problems?

With your septic tank tucked away out of sight underground, it’s difficult to know what’s going on down there. If you start to get problems with your septic tank, it can get even trickier. How can you fix something when you can’t even see what’s happened?

Many gardens have well established trees or shrubs within their boundary, and often there’s no problem and they coexist quite happily with a septic tank. But sometimes property owners can have tree root problems in their septic tank, or the pipework running to and from the tank. Tree roots can be quite a formidable force underground and can be strong enough to break through the walls of a septic tank, or to penetrate the pipework it connects to. Once this has happened, it can lead to problems such as groundwater leaking into the tank, or blockages in the pipework caused by a build-up of tree roots.

So, how do you know if your septic tank has tree root problems, and what can you do about it? Unless you can see any tree roots above ground through manhole covers or inspection chambers, it’s likely that you’d only know of tree root problems if you have been told by someone who’s spotted them, perhaps the tanker operative when your system was last emptied. If tree roots have caused a problem in your septic tank, then you’ll need some expert advice. It can often be difficult to carry out any repairs on tree root damage, because the structural integrity of the tank is compromised once tree roots have broken through the walls. Unfortunately, it’s not as straightforward as cutting them out and patching it up, and in many cases a replacement tank is required. If you’ve been told that a repair is possible, it’s usually good to get a second opinion on that, because the longevity of such a repair can’t usually be guaranteed, and in some cases it could invalidate a manufacturer warranty on the tank.

It’s not all doom and gloom though. If an expert notices that the tree root damage is to the pipework running from your property to the septic tank, it’s possible that the roots can be cut out and the pipework repaired which is both less intrusive and less costly. So, it’s important to know what you are dealing with before you worry about what the solution might look like.

Tree roots near underground drainage pipework

Tree roots are one of the most common reasons a septic tank needs attention, and what happens next depends on whether they have reached the tank itself or just the pipework. Either way, it pays to know where you stand before any work starts.

Did you know?

Most buildings insurance policies will provide cover for tree root problems in septic tanks, as well as within the pipework running to and from them. Here at UKDP, we are experts both in septic tanks and helping with insurance claims for property owners to get any problems sorted out. Handy, right? So, if you suspect tree root problems somewhere in your drainage system, or you’ve been advised that tree roots have been noticed, get in touch with our team today to find out more about how we can help.

Frequently Asked Questions

How do I get rid of tree roots in a septic tank or its pipes?

Roots in the pipework can often be cut out and the pipe repaired or relined. Roots that have broken into the tank itself are harder, and that usually means replacing the tank. A survey shows how far the roots have got.

Do chemical root killers work in a septic tank?

Avoid them. Root-killing chemicals can harm the bacteria the tank relies on, and they don't fix the damage the roots have already done. Cutting the roots out and repairing the pipe is the proper fix.

Which trees cause the most damage to septic tanks?

Fast-growing, moisture-seeking species like willow, poplar and some conifers are the usual culprits. If you're planting near a tank or soakaway, keep thirsty trees well away.

Is tree root damage to a septic tank covered by insurance?

Often, yes. Tree root damage is usually treated as sudden and accidental, so buildings insurance may cover it. We can inspect it, evidence the cause and help with the claim.