Underground drains are out of sight, so damage often goes unnoticed until it causes a problem. Many older homes in Southampton still have their original clay drains, which can crack, shift at the joints or be invaded by roots over time.
These are the signs worth watching for.
Warning signs
Blockages that keep coming back
A drain that blocks every few weeks or months, even after being cleared, often has a defect that catches debris: a displaced joint, a crack, a dip in the pipe or roots. See what causes recurring drain blockages.
Persistent smells
A drain smell outside, or inside when no trap has dried out, can mean waste is escaping through a crack or sitting in a dip. Our guide to bad smells from drains covers other causes to rule out first.
Rats
Rats can enter homes through broken drains. If you have rats in the garden, under the floor or in the walls with no obvious entry point, a damaged drain is a common route.
Sinking paving or ground
Water leaking from a broken drain can wash soil away. Paving that dips, a small hole appearing in the lawn, or ground that sinks along the line of a drain are signs to take seriously.
Damp walls or floors
A leaking drain close to the house can cause damp patches on walls or floors near where it runs.
Unusually lush grass
A strip of greener, faster-growing grass along the line of a drain can indicate water and nutrients leaking into the soil.
Slow drainage and gurgling
A partially collapsed pipe restricts flow, so fittings drain slowly and gurgle. See why drains gurgle.
What causes drains to break
- Tree roots entering through joints and cracks. See tree roots in drains.
- Age and material: older clay pipes and joints can crack or shift.
- Ground movement, including shrinking and swelling clay soils.
- Heavy loads from vehicles or building work above a shallow drain.
- Previous poor workmanship, such as badly made connections.
How it is diagnosed
A CCTV drain survey is the reliable way to find out. A camera is passed through the drain to show exactly what the damage is, where it is and how deep. That means any repair is based on evidence rather than guesswork, and you only pay to fix what actually needs fixing.
What happens next
The right repair depends on the type of damage, its position, how deep the drain is and what is above it. Some defects can be repaired from inside the pipe without digging; others need the damaged section excavated and replaced. We explain the options and why we recommend one, so you can decide.
Check your home insurance too. Some policies cover accidental damage to underground pipes, and insurers usually want to be told before work begins.
Find out more about drain repairs, or read about drain surveys before buying a house.