New Build Drainage Problems Andover | What Surveys Find
New-build drains on Andover estates often hide debris, misaligned joints and shared sewer confusion. A CCTV survey shows what developer sign-off missed.
A new house shouldn't have drainage problems. That's the assumption, anyway. But in five years of surveying newer Andover estates, including Foxcotte, Picket Twenty, East Anton and Saxon Fields, the camera tells a different story surprisingly often.
New doesn't mean defect-free. It means the defects are younger.
What the Camera Actually Finds on New Builds
The most common finds on post-2010 Andover estate drainage aren't cracks from ground movement or root ingress from mature trees. They're construction-stage problems that were never caught before handover.
Building debris. Mortar lumps, brick fragments, even a plastic bag or cable tie are regular finds. They drop in during groundworks and sit at low spots until they cause a blockage. On one Foxcotte job we ran last spring, the camera found a concrete plug roughly 60 mm across sitting in a 100 mm lateral, about 4 metres from the inspection chamber. The homeowner had been dealing with slow drainage since month two of occupation. The developer's sign-off had been done with a pressure test, not a camera survey.
Misaligned or displaced push-fit joints. Plastic push-fit pipe is quick to lay, which is why it's used on volume builds. If a joint isn't fully seated before backfill, it can be displaced by compaction. The gap lets in fine silt, and over time you get a partial blockage or, worse, a void forming in the ground around it.
Pipe bellies. A belly is a low sag where the pipe hasn't been bedded evenly. Water sits there rather than running to the sewer. Grease and debris accumulate. It doesn't block immediately, so it passes a flow test. A CCTV survey grades it on the MSCC5 scale.
Shared private sewers. This is where it gets complicated.
The Shared Sewer Problem Nobody Explains at Completion
On many Andover estates, the lateral drain from your property joins a shared private sewer before it reaches the public sewer adopted by Southern Water. That shared section is jointly owned by the properties connected to it, not maintained by the water company and not covered by your individual buildings insurance as a matter of course.
Most new-build buyers don't know this until something goes wrong and they're arguing with a neighbour about whose responsibility it is to fix a collapsed joint under a shared driveway.
| Drain section | Who owns it | Who maintains it |
|---|---|---|
| Inside your boundary | You | You |
| Shared private sewer (pre-adoption) | All connected owners jointly | All connected owners jointly |
| Adopted public sewer | Southern Water | Southern Water |
A drainage search at conveyance should show the adoption status, but on estates still being built out, that picture can be incomplete.
What a CCTV Survey Picks Up That a Snagging List Won't
Standard snagging inspections are visual, above-ground checks. A CCTV drain survey sends a camera through the pipe and logs condition against MSCC5 defect codes. It shows:
- Debris location and type
- Joint displacement to the millimetre
- Belly depth and length
- Any pipe deformation from poor bedding
- Whether your drain connects where the as-built drawings say it does
That last one matters more than it sounds. On a fast-moving estate build, a connection occasionally ends up routed differently from the drawing. You find out when there's a problem and the dig goes in the wrong place.
A Foxcotte Job, Before and After
A couple who'd moved into a detached new-build on the Foxcotte development called us about eight months after completion. Slow drainage from the ground-floor WC, occasional gurgling from the kitchen. Their developer's customer care team had rodded the drain twice and found nothing.
We ran a CCTV survey from the external inspection chamber. About 6 metres in, the camera hit a mortar deposit narrowing the pipe by roughly 40%. Further on, a push-fit joint was displaced by about 15 mm, letting in a trickle of fine sand each time it rained.
We cleared the debris with high-pressure water jetting, then relined the section across the displaced joint. The homeowner sent the survey report to the developer's warranty team. They didn't pay without a conversation, but they paid. The remedial work carries our 20-year guarantee.
The broader point: the developer's pressure test at handover showed the drain was clear. It was, at that point. The mortar had broken loose from a chamber wall a few weeks later.
When to Book a Survey on a New Build
You don't have to wait for a problem. A survey in the first two years keeps you within most developer warranty windows. If you're buying a resale new-build, a pre-purchase drainage survey is as worth having as a structural survey.
Drainsco covers Andover and the SP10 and SP11 postcodes, with engineers available 24/7. There's no call-out fee, and you'll get a clear price before we start. Call us and describe what you're seeing. We'll tell you whether a survey is the right next step.
Priya Nair, CCTV survey and diagnosis specialist
Priya is the one who reads the camera footage. She handles the survey work, the pre-purchase reports and the build-over enquiries, and she will happily explain why a drain that keeps blocking almost always has a cause worth finding rather than a clear-out worth repeating.
Blocked drain in Andover?
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