A CCTV drain survey in Farnham: what we found

This is a redacted engineering insight from a recent survey in Farnham. Identifying project details have been removed. The findings below relate only to the drains that were inspected and should not be treated as a diagnosis of every drainage system in the area.

A CCTV drain survey was commissioned to clarify how a drainage system described by the owner as Victorian was connected, where water entered and left the system, and whether the camera could locate a separate leak reportedly identified by the water company.

The survey provided useful answers about several local connections and pipe defects. It did not establish the full drainage route, confirm the final discharge point, or identify the location of the separately reported leak.

What the camera was able to trace

All seven inspected sections were recorded as private 100 mm vitrified clay pipes. CCTV tracing identified connections between access points and branches leading towards two gullies, a soil vent pipe and a vent connection.

The soil vent pipe connection confirms that part of the system serves foul drainage. However, the survey records do not show what feeds each gully, whether foul and surface water are kept separate or combined, or where the system finally discharges.

That distinction matters. A camera survey can show the condition and direction of the pipes it reaches, but it cannot safely fill in unseen parts of the network. Where a trace stops, the onward route remains unconfirmed.

Roots and a crack stopped one downstream inspection

One downstream section was recorded as not serviceable. The camera found root growth at a lengthways crack relatively close to the access point, followed by coarse deposits further along the pipe.

The inspection had to stop before the route could be traced onwards. This leaves the continuation and condition of the pipe beyond that point unknown.

Roots often enter through openings such as damaged pipework or imperfect joints. In this case, the observed crack and root entry show local damage and a serviceability problem. The crack on its own, however, does not prove that water is actively leaking from that location.

A second branch was flowing, but was not sound

An upstream branch also could not be traced beyond its inspection limit. It contained a crack running around the pipe, a fracture with roots present, and coarse deposits close to where the survey stopped.

This branch was recorded as flowing satisfactorily at the time of inspection. That is useful evidence, but it should not be mistaken for evidence that the pipe is in good condition. Fractures affect the integrity of the pipe, while roots and deposits can increase the risk of obstruction. A flowing drain may still have damaged fabric or struggle when flows are higher.

Other defects found in the inspected lengths

The survey also recorded displaced joints near one gully connection and in another drain section. In the latter section, there was also a lengthways fracture and deposits.

A displaced joint means the ends of two pipe sections are no longer properly aligned. This can affect the pipe connection and create a point where debris may collect or roots may gain access. As with the upstream branch, recorded flow was satisfactory in these sections, but that does not remove the significance of the defects seen on camera.

Two short connections, serving a gully and a vent, were recorded as serviceable within the lengths inspected, with no defects noted.

A failed leakage test at the soil vent connection

A short soil vent pipe connection was recorded as not serviceable after a failed leakage test. The CCTV inspection also found a crack around the pipe.

This is evidence of a watertightness problem in that connection. It does not establish that it was the source of the separate leak reported by the water company. The survey was clear that the reported leak location remained unresolved.

Why no repair was specified for every defect

Some inspected sections were recorded for planned demolition, which is why repairs were not specified for every defect. This should not be read as confirmation that those pipes were defect-free; defects were still recorded in the survey.

For the two incomplete traces, further investigation was identified as planned work. The surveyor considered that water was likely entering from upstream of one untraced point and travelling towards another. Extensive high-pressure water jetting, and possibly excavation, may be needed to establish the full route and condition.

What this means for homeowners nearby

This is one property-specific, redacted survey rather than a statement about all homes in Farnham. Still, it illustrates several practical points for homeowners with older drainage:

• A drain can be flowing while still having cracks, fractures, displaced joints or root intrusion.
• A CCTV survey only confirms what the camera can reach and record.
• Gullies and vents do not, by themselves, prove whether a system is separate or combined, or where it discharges.
• A failed leakage test can identify a watertightness issue, but further tracing may still be needed before linking it to a reported leak.
• Where roots, deposits or damage stop the camera, cleaning or investigative work may be necessary before the route can be understood.

A clear survey report helps separate observed facts from unanswered questions. If you need to understand the accessible parts of your drainage system, see our CCTV drainage surveys service. Where a defect has been properly assessed, options may include drain relining or drain repair, depending on the pipe condition, access and scope of the work.

To discuss a CCTV drainage survey or request a quotation, please contact Clever Works.