A standard homebuyer’s or building survey does not go underground. Your surveyor will lift a manhole cover if there is one and look at what they can see from the surface. Nobody puts a camera down the pipe unless you ask for it.
That is the gap. Drainage is one of the few things about a house that can produce a five-figure bill, is invisible from the surface, and is not covered by the survey most people assume covers everything.
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What the survey tells you
- What the drainage is made of. Vitrified clay, pitch fibre or PVC, and the difference matters enormously. Pitch fibre — standard across post-war estates and throughout Telford — cannot be repaired in place.
- Whether anything is structurally wrong, graded section by section on the Drain Repair Book scale so urgent and cosmetic are separated.
- Where the drainage actually runs, on a site plan. For most properties this drawing has never existed before.
- Whether it is shared, and where your responsibility ends.
- Whether anything has been built over it — a frequent finding on properties that have been extended.
What you do with the report
Renegotiate. A graded, coded report from a certified surveyor is evidence. It is considerably harder for a seller to dismiss than a photograph and a worry.
Budget properly. Knowing you will need work in five years is different from discovering it in month three.
Or stop worrying about it. A good proportion of the surveys we carry out come back graded A with nothing structurally wrong. That is a real outcome, not a wasted fee — it takes drainage off the list of things to negotiate over, and the recording is there if the question ever comes up again.
When to book it
Alongside your building survey, not after it. The report comes back the same day, so it fits inside the window where you still have room to negotiate. Leaving it until the survey has flagged “possible drainage issue” costs you a fortnight you may not have.
We do not need you to be there, only access to the manholes and any locked gates. Plenty of our pre-purchase surveys are carried out with the buyer nowhere near the property.
What it is worth knowing before you commit
Since the 2011 private sewer transfer, most shared drainage and everything beyond the property boundary belongs to Severn Trent rather than the homeowner. That cuts both ways: a defect past the boundary may not be your problem at all, and a survey that establishes where the boundary falls can be worth more than the survey fee on its own.
Across the Black Country and south Staffordshire there is a further wrinkle: South Staffs Water supplies the drinking water in much of this area but is not the sewerage undertaker. For drainage, Severn Trent is who you want.
Common questions
Will my mortgage lender ask for one? Not usually as a condition, though a valuer flagging drainage can trigger a retention. Most people commission one because their own surveyor recommended it, or because the property is old, extended, or on ground with a mining history.
How long does it take? One to three hours on site for most houses. The report is with you the same day.
The house is new — do I still need one? Often more than you would for an older one. Drainage laid during construction is not always laid correctly, and while a warranty still runs the fault may be someone else’s to put right.
What if the survey finds something? Every section is graded, so you know what is urgent and what can wait. We do not carry out drain repairs or excavation, so there is no incentive for us to find work that isn’t there — and no quote follows the report.
Can you survey if the drains are blocked? We would clear them first; the camera cannot see through standing water. Both in one visit.
Related: CCTV drain surveys · Build over agreements · Drain mapping and site plans Guides: What a homebuyer drain survey actually finds · Pitch fibre or clay
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