Why does my drain keep blocking?

We regularly visit homes and businesses across Leicester and the surrounding areas where the same drain has been cleared several times, only for the problem to return weeks or months later.

When that happens, the blockage itself is rarely the real issue. Repeated blockages almost always point to something going wrong inside the drainage system.

Clearing the drain fixes the symptom. Finding the cause stops it happening again.

Here are the most common reasons drains repeatedly block in Leicester properties.

 

1. Tree roots inside older pipework

Many properties in areas such as Clarendon Park, Knighton, Aylestone and parts of Highfields still use older clay drainage pipes.

Clay pipes last a long time, but the joints naturally weaken with age. Tree roots are drawn to moisture, so even a tiny gap gives them an entry point.

Once roots get inside, they:

• Catch wipes and debris
  • Slow water flow
  • Cause repeated blockages
  • Gradually damage the pipe itself

Simply clearing the blockage will not solve the problem if roots remain. Proper root cutting, and sometimes drain relining, is usually needed to stop the cycle repeating.

 

2. Scale build-up inside the pipe

Over years of use, drains can develop a hard internal coating made from grease, soap residue and mineral deposits.

This build-up narrows the pipe without you noticing. Waste catches more easily and blockages become more frequent.

Drain rods often punch a hole through the middle, which restores flow temporarily, but the restriction stays in place along the pipe walls.

High-pressure jetting is normally required to properly clean the pipe and reset it back to full capacity.

 

3. Damaged or partially collapsed drains

Recurring blockages are often linked to structural damage underground.

Typical problems include:

• Cracked pipe sections
  • Displaced joints
  • Partial collapses
  • Movement caused by ground settling

Waste collects on these damaged areas and gradually forms another blockage.

If your drain blocks in the same spot each time, there is a good chance the pipe itself is damaged. A CCTV drain survey removes the guesswork by showing exactly what is happening underground.

 

4. Incorrect pipe gradient

Drains rely entirely on gravity. The slope of the pipe has to be right.

If the fall is too shallow, solids settle instead of moving through.
If it is too steep, water runs ahead and leaves debris behind.

Both situations lead to repeat blockages.

Incorrect gradients are often the result of older installation work, extensions added years later, or gradual ground movement over time. Clearing the drain alone will not permanently fix this type of issue.

 

5. Previous drain work only solved part of the problem

We often attend Leicester properties where drains have been cleared several times already.

Common situations include:

• Only part of the blockage removed
  • Debris pushed further down the system
  • No camera inspection carried out
  • Structural issues never identified

The drain works for a short period, then blocks again. Not because the problem returned, but because it was never fully solved in the first place.

Why recurring blockages should not be ignored

A drain that keeps blocking is effectively giving you an early warning.

Left unresolved, ongoing problems can lead to:

• Internal flooding
  • Overflowing external drains
  • Damage to property and flooring
  • Rat entry through damaged pipework
  • Increasing repair costs over time

Small issues underground tend to become larger and more expensive if left alone.

The right way to fix a recurring drain problem

The proper approach starts with inspection rather than repeated clearance.

A professional visit may involve:

• CCTV drain survey
  • High-pressure jetting
  • Root removal
  • Drain relining
  • Local structural repairs

The aim is not just to get water flowing again. It is to understand why the blockage keeps happening and stop it returning.

Final thought

If your drain blocks once, it may just be bad luck.

If it keeps blocking, there is almost always an underlying cause.

Avoid paying repeatedly for temporary fixes.
Identify the problem properly.
Fix it once. Fix it properly.

Frequently asked questions

Why does my drain keep blocking after being cleared?
Recurring blockages are usually caused by roots, scale build-up, structural damage or incorrect pipe gradients. Clearing the surface obstruction alone does not resolve the underlying issue.

Do I need a CCTV drain survey in Leicester?
If blockages keep returning or structural damage is suspected, a CCTV survey helps identify the exact cause quickly.

Can tree roots really cause repeated blockages?
Yes. Root ingress is one of the most common causes of recurring problems in older Leicester drainage systems.

Is high-pressure jetting better than drain rods?
For repeat blockages, jetting is often more effective because it cleans the pipe walls rather than just opening a temporary path.

Will the drain need digging up?
Not always. Many structural problems can now be repaired using relining techniques without excavation. A CCTV inspection determines the best option.