What is a CCTV drain survey?

A small waterproof camera on a flexible cable or a wheeled crawler is fed into your drain through an inspection chamber, gully or access point. It sends a live picture to a screen and records what it sees. The engineer can then show you the inside of pipes you would otherwise never see.

What can a survey show?

cracked, broken or collapsed sections of pipe
joints that have slipped out of line
tree roots growing into the pipe
build-up of grease, scale or silt
sections that sag and hold water
misconnected pipes or a drain that goes somewhere unexpected
the position and depth of the pipe, if the engineer also uses a locating device

When is a survey worth having?

A survey makes sense when a drain keeps blocking after it has been cleared, when there is a lasting smell, when damp patches appear near a drain run, or when a gully or garden area stays wet for no obvious reason. It also helps before you build over or near a drain, because a pipe in poor condition is much cheaper to deal with before the work starts.

If you plan to build over, or within 3 metres of, a public sewer, the Building Regulations guidance in Approved Document H says the owner of the sewer should be consulted. Here that is usually Thames Water, which says you will usually need its build over agreement before work starts.

Should I have a survey before buying a house?

It is worth thinking about, particularly for an older property or one with large trees nearby. The searches your solicitor orders will normally show whether the home is connected to the public sewer and whether the drains are shared. They do not tell you what condition the pipes are in.

A survey before you exchange contracts can reveal defects that would otherwise become your repair bill. If it does, you can ask the seller to put it right, negotiate on the price, or walk away. Ask your solicitor or surveyor how it fits your timetable, and arrange access with the seller early, since the engineer will need to reach the inspection chambers.

What happens on the day?

The engineer lifts the inspection chamber cover, sometimes clears loose debris, and runs the camera along the pipe. If the pipe is full of water or blocked, they may need to clear it first for a clear picture. They note where any defects are, usually by distance from the access point.

Afterwards you can expect a recording and a written report, though you should confirm exactly what you will receive before the visit. The report should show the defects found and where the drain runs.

What if the survey finds a problem?

That depends on what is found and whose pipe it is. A drain that serves only your home within your boundary is normally yours to repair. Since October 2011, a shared drain, or a lateral drain beyond your boundary, has generally been the water company's responsibility. In this area that is usually Thames Water, even if your water bill comes from Affinity Water. Your bill shows who handles your sewerage.

If a survey records a defect on a shared pipe, send the findings to your sewerage company. If the defect is on your own pipe, you can enquire here about repairs.

Can a camera see everything?

No. Small bore pipes, tight bends, pipes full of silt or blockages and severely collapsed sections can limit how far a camera can travel. If it cannot pass, the survey may be incomplete, and the report should say so. Flushing the pipe first often helps.

Is a survey only for houses?

No. Landlords, managers of blocks of flats and businesses use surveys too, for example before a lease ends or when planning an extension. Say in your enquiry what kind of property it is and whether the drains are shared with neighbouring units.

What should I put in my enquiry?

your postcode and the type of property
whether you are buying, selling, building or simply having trouble
how old the property is, if you know
where the inspection chambers are, if you know
whether the drains are shared
any dates you are working to

What happens after I send it?

Enquiring is free and you are not committed to anything. Any work and its cost are agreed between you and the engineer.

Who you will hear from

We pass your enquiry to one local drainage engineer, if one covers your postcode. It is never sent to a list of companies. If nobody covers your postcode, we will tell you and will not pass your details on.