The short answer
For diagnosis, a CCTV survey is almost always the right first step. A camera on a flexible rod or crawler is pushed through the drain from a chamber, giving live, recorded footage of the inside of the pipe — it pinpoints cracks, root ingress, displaced joints, blockages and collapses, and locates them to the metre, all without digging. Dig-and-inspect means physically excavating to expose the pipe, which is disruptive, slower and costlier and only makes sense once you already know roughly where the fault is and you need to repair it. The sensible order is survey first, dig only if the repair requires it: the CCTV survey tells you what is wrong and exactly where, so any excavation that follows is targeted rather than exploratory.
Before fixing a drain you need to know what is wrong and where. A camera survey and physical excavation are the two ways to find out, but they sit at very different points in the process. Here is how they compare.
CCTV vs dig
- CCTV surveyCamera inside the pipe
- Dig-and-inspectExcavate to expose pipe
- DisruptionCCTV none; dig high
- Locates faultCCTV to the metre
- Best orderSurvey first, dig if needed
How each approach works
A CCTV drain survey sends a small waterproof camera through the pipe from an access point such as a manhole or rodding eye. On smaller domestic drains the camera sits on a push-rod; on larger runs a self-propelled crawler is used. The operator watches a live feed, records footage, and uses a sonde and locating equipment to mark where each defect lies on the surface above. The result is a report with video evidence showing the condition of the pipe along its length — blockages, cracks, root intrusion, displaced or open joints, scale, standing water from a fall problem, and any collapse.
Dig-and-inspect is the older, direct method: excavate down to the pipe and look at it. It gives an unarguable view of the section you uncover and is sometimes the only way to confirm a fault on a stretch a camera cannot pass — but it is invasive, you can only see what you dig up, and exploratory digging without knowing where to look is slow and expensive. In modern practice it is reserved for the repair stage, not the diagnosis stage.
| Factor | CCTV survey | Dig-and-inspect |
|---|---|---|
| Method | Camera inside the pipe | Excavate to expose pipe |
| Disruption | None to the surface | High, breaks ground |
| Speed | Often same visit | Slower, depends on depth |
| Cost | Lower (survey fee) | Higher (labour, reinstatement) |
| Locates fault | Yes, to the metre | Only where you dig |
| Sees whole run | Yes | Only the exposed section |
| Best stage | Diagnosis | Repair, once located |
Indicative comparison for guidance. Costs vary by access, length and depth.
When a CCTV survey is the right call
A camera survey is the appropriate choice almost any time you need to understand a drain rather than just clear it. Recurring blockages that return after clearing usually have an underlying cause — grease, roots, a partial collapse or a fall problem — and a survey identifies it so you stop treating symptoms. Surveys are also routine for pre-purchase home buyer checks, for confirming who is responsible for a shared run, for insurance claims after subsidence or a leak, and for planning a repair so the contractor knows exactly what they are dealing with.
Because it is non-destructive, fast and locates faults precisely, a survey saves money overall: it prevents needless digging, shows whether a no-dig repair such as relining is feasible, and gives documented evidence rather than guesswork. For most homeowners facing a mystery drain problem, the survey is the diagnostic step that makes every following decision better informed.
When excavation is genuinely needed
Digging has its place, but at the repair end, not the diagnosis end. If a survey reveals a collapsed section, a badly displaced joint, or damage that cannot be repaired from inside the pipe, excavation may be the only way to replace or rebuild that stretch. Some repairs — open-cut replacement of a short failed length, or installing a new connection — necessarily break ground. Occasionally a camera cannot pass a severe blockage or collapse, and a targeted dig at the located point is needed to get past it.
The deciding principle is sequence. Survey first to learn what is wrong and exactly where; then choose the repair. Many faults that once meant digging can now be fixed with no-dig methods like patch lining or full relining, which a survey will confirm as an option. Where excavation is unavoidable, the survey ensures it is small, precise and confined to the failed section rather than a long exploratory trench. So the honest answer to which is better is that they are not really rivals — a CCTV survey diagnoses, and a dig, when needed, repairs.
What a survey report should tell you
A worthwhile CCTV survey produces more than a video. The report should identify each defect found, its position along the run measured from a known access point, and its severity, often using a recognised drainage condition grading so that minor wear is distinguished from serious structural failure. It should note the pipe material and diameter, any change in fall or signs of standing water, the presence and extent of root ingress, and a clear recommendation for what, if anything, needs doing. With that information you can make an informed decision rather than relying on a verbal account of what the camera showed.
This documentation has practical value beyond the immediate repair. For a property purchase, a survey report informs negotiation and flags future liabilities. For an insurance claim after subsidence, a leak or accidental damage, insurers typically want the evidence a survey provides. Where a blockage or defect sits on a shared or boundary drain, the located footage helps establish whether the problem is yours or the sewerage company's responsibility. And if a repair is needed, the report lets you obtain comparable quotes from more than one contractor, because they are all pricing against the same evidence.
When commissioning a survey, it is reasonable to ask what you will receive — recorded footage, a written report with locations and gradings, and a recommendation — and whether the cost is refundable or credited against any repair work. A reputable firm will explain the findings in plain terms and show you the relevant footage rather than simply asserting that expensive work is needed. That transparency is the difference between a survey that genuinely informs your decision and one that exists only to justify a quote.
Frequently asked questions
Do I need a CCTV survey before digging up a drain?
In nearly all cases, yes. A survey shows what is wrong and locates it precisely, so any excavation is small and in the right place. Digging without a survey is guesswork that often means a larger hole, more reinstatement and higher cost than necessary.
Can a CCTV survey see every drain problem?
It sees the inside of the pipe extremely well, identifying cracks, roots, displaced joints, blockages, scale and collapses, and locates them on the surface. Its main limit is that a camera cannot always pass a severe blockage or total collapse, in which case a targeted dig at the located point is used to get past it.
Is a CCTV survey worth it before buying a house?
It is commonly recommended, especially for older properties or where there is a history of drainage problems. Replacing a collapsed underground drain is costly, so a pre-purchase survey that reveals the pipe's condition can inform negotiation or flag a problem before you commit.
Sources & further reading
Figures on this page are typical UK ranges drawn from published cost guides and are intended as guidance, not a quotation.