Guides · Harrow

CCTV Drain Surveys for Homebuyers

A standard homebuyer survey does not look inside the drains. Surveyors will note what is visible at ground level and will usually recommend a specialist drainage inspection if something concerns them, but they do not put a camera down the pipe. For a certain kind of property that gap is the most expensive thing missing from the report, and this page explains when it is worth closing.

What a drain survey finds that a building survey does not

A CCTV survey sends a camera through the underground run and records the condition of the pipe along its whole length. It identifies cracks, dropped and open joints, displaced sections, partial collapse, root ingress, standing water indicating a fall problem, and misconnections where a surface water pipe has been joined to a foul run or vice versa. None of that is visible from above ground, and none of it appears in a standard building survey. It also produces a recording, which is what gives you something to negotiate with.

When it is worth doing

It is most worth doing on older properties with original drainage, on properties with mature trees close to the run, on anything that has been extended - because extensions frequently build over or reroute drainage, sometimes badly - and on any property where the seller mentions past drainage problems or where the drainage and water search flags something. It is least worth doing on modern properties with plastic drainage and no trees nearby, where the likelihood of finding anything material is low.

Why this matters in Harrow specifically

A large proportion of the housing stock across the borough falls squarely into the category where a survey earns its cost. The Victorian and inter-war terraces and semis across Wealdstone, Kenton, North Harrow and South Harrow were built on clay drainage that is now beyond its design life. The larger properties in Pinner, Stanmore and Harrow Weald combine that ageing pipework with long private drain runs and substantial mature trees. And extensions and loft conversions are widespread across the borough, which means a meaningful number of properties have drainage that has been altered - sometimes built over, occasionally without proper approval. If you are buying a pre-1940s property here, a drain survey is one of the better-value checks available.

What to do with the findings

A survey that finds nothing has bought certainty for a modest sum. A survey that finds something gives you three options: renegotiate the price by the cost of the repair, ask the seller to carry out the work before completion, or walk away if the defect is serious. Drainage repairs range from a straightforward localised patch to full excavation and replacement of a run under a driveway or extension, and the difference between those figures is substantial - which is precisely why finding out before exchange rather than after matters.

A related check worth making at the same time

Ask whether the property has been built over or close to a public sewer or lateral drain. Since the 2011 transfer, a great many properties in the borough have Thames Water assets running under gardens and, in some cases, under later extensions. Building over a public sewer without agreement can create problems on resale and complicate any future work. The drainage and water search from your conveyancer will show the recorded public system, and a survey will show what is physically there - which is not always the same thing.

Common questions

Will my mortgage lender require a drain survey?

Generally not as standard, though a lender may require one if the valuer or surveyor flags a concern. The absence of a lender requirement is not an indication the drains are sound - it reflects that lenders are assessing security value rather than inspecting condition.

How long does a survey take?

A typical domestic survey takes one to two hours on site, depending on the length of the run and how accessible the chambers are. The recording and written report normally follow within a day or two. Blocked or heavily silted runs may need jetting before the camera can pass, which adds time and cost.

Can I ask the seller to pay for it?

You can ask, though buyers usually commission and pay for their own so the report is independent and addressed to them. Where a survey finds a defect, the cost is usually recovered many times over in the renegotiation.