A CCTV drain survey in Guildford: what we found

This case study is based on an approved, redacted survey summary. Project-specific identifiers and other identifying details have been removed. It relates to one property in Guildford and should not be treated as a diagnosis of drainage at other homes.

A CCTV drainage survey was commissioned after water pooling had been reported around a property in Guildford. The inspection covered accessible foul and surface water drainage runs.

The camera evidence identified several local issues that could be relevant to the reported pooling, alongside foul drainage maintenance and repair considerations. It also showed the limits of the inspection: part of the foul system could not be surveyed until further cleaning and emptying work is completed.

What the survey could confirm

The accessible drainage was recorded as two separate private systems:

• a foul water system, which carries wastewater from sanitary appliances; and
• a surface water system, which carries rainwater.

The surface water route was traced to a soakaway. A soakaway is an underground feature designed to allow rainwater to disperse into surrounding ground.

The survey did not record structural defects or obstructions in the inspected surface water pipe runs. However, following a pipe to a soakaway does not prove how quickly the soakaway can absorb water, or whether it has sufficient capacity during heavy rainfall.

Rainwater connections and pooling

Two rainwater pipes were found not to be correctly connected. This creates plausible points where rainwater could escape locally, and may have contributed to the reported pooling.

Importantly, the inspection did not establish that these pipes discharged to the wrong drainage system. Nor did it prove that they were the only cause of the pooling. CCTV findings need to be read alongside the layout of the site, rainfall conditions and any further testing that may be appropriate.

A gully was also found to be dry, with a visible crack in its pot and a displaced pipe joint immediately upstream. A gully is the grated inlet that receives water at ground level. Its water seal normally helps limit drain odours; when a gully is dry, there can be concern that this seal is not being retained.

The cracked gully and displaced joint raise concerns about how securely water is being contained and conveyed. They are another possible source of local wetting, but the limited inspection did not demonstrate active leakage or establish a single cause of the pooling.

What the camera found in the foul drains

The foul drainage inspection identified several distinct findings:

• Heavy grease deposits stopped the camera progressing along one branch shortly after entry. This was a material local restriction, leaving the remainder of that branch unassessed.
• Encrustation was recorded at a joint in another branch. Encrustation is a hard build-up on the inside of a pipe or around a joint and can be a maintenance concern.
• Local lengthways cracks were recorded in a toilet waste branch and another section of foul pipework. These are defects in the pipe material and may affect watertightness. Active leakage was not demonstrated by pressure testing.
• Minor root entry was recorded in two locations. It was assessed as suitable for monitoring rather than being presented as evidence of an immediate blockage or failure.

The inspected chambers were recorded in satisfactory condition, with no evidence of surcharge. In drainage, surcharge means wastewater rising or backing up beyond the normal level within a system. No active flow was recorded in those chambers at the time of inspection.

Why the downstream condition remains unknown

The foul system could not be fully traced downstream because a tank requires emptying before the remaining route can be inspected. The completed CCTV survey therefore did not confirm the downstream route shown on the drainage drawing.

The condition, capacity and operating performance of the tank were not established. Neither were the condition of associated distribution components nor the destination and suitability of the final discharge. A separate assessment of the tank and discharge arrangements was understood to have already been commissioned.

This is an important distinction: a CCTV survey can provide strong visual evidence for the sections it reaches, but it cannot confirm the condition of pipework or assets it cannot access.

What this means for homeowners in Guildford

This survey illustrates why water pooling should not automatically be attributed to one visible feature. Here, incorrectly connected rainwater pipes and defects around a gully were plausible local contributors, while soakaway performance remained unproven and some foul drainage remained inaccessible.

For homeowners noticing recurring wet areas, slow drainage, odours or uncertainty about where rainwater is going, a survey can help separate confirmed findings from assumptions. The next step should reflect the evidence: this may include cleaning to restore access, a return CCTV inspection, repair planning, or investigation of drainage performance where the available evidence does not answer the question.

A CCTV drainage survey can document accessible pipe condition and identify where further investigation is needed. Where rainwater disposal requires assessment, BRE 365 percolation testing may be relevant to a proposed or investigated soakaway arrangement. Repairs should be scoped from confirmed defects and access constraints, rather than from a camera observation alone.

If you have concerns about drainage at a property in Guildford, request a quotation for an appropriate survey or investigation.