CCTV drain surveys and high-pressure jetting

Most blocked drains are a one-off. A plunger clears the toilet, or rods clear a gully, and that is the end of it. When the same drain blocks again and again, or smells, or water backs up in more than one place, the cause is usually something you cannot see: a root, a crack, a sunken section, a build-up of fat, or a pipe that was laid badly in the first place.

That is where a drainage firm comes in with two main tools: a CCTV camera to see inside the pipe, and a high-pressure water jetter to clean it. This page explains what each is for, what a survey report should tell you, and what to ask before paying.

Signs it is more than a simple blockage

• The same toilet, sink or gully blocks repeatedly, even after clearing.
• Several fittings drain slowly at once, especially on the ground floor.
• Water rises in an inspection chamber or a gully when a toilet is flushed.
• There is a persistent sewage smell outside that is not just a dry trap.
• Patches of the garden or drive stay damp, or the ground over a drain is sinking.
• You are buying an older house and want to know the state of the drains.

For the first steps on a single fitting, see blocked toilet and blocked sink. For smells, start with drain smells. This page picks up where those leave off.

What a CCTV drain survey is

A drainage engineer pushes a small waterproof camera on a flexible rod along the drain, usually from an inspection chamber, a rodding point or, sometimes, a removed toilet. The camera sends live pictures to a screen, and most systems record the footage and measure how far along the pipe the camera is.

The engineer looks for:

• blockages and what they are made of;
• roots getting in through joints;
• cracks, fractures and collapsed sections;
• joints that have moved apart or dropped;
• dips where water sits, sometimes called a belly or sag;
• fat and scale build-up;
• the route of the drain and where it joins others.

A camera survey is also used to find where a drain runs, to check a new drain before it is covered, and to see whether a drain belongs to you or is shared. Outside drains explains how responsibility usually splits between your drain and the public sewer.

What the report is for

A good survey comes with a written report and the footage. The report usually includes a plan or sketch of the drain runs, a list of defects with their positions along the pipe, still images, and recommendations.

The report is useful for:

• deciding whether to repair, reline or replace a section;
• comparing quotes, because every firm can see the same evidence;
• an insurance claim, if your policy covers drains. Leak insurance claims covers what insurers tend to ask for;
• a house purchase, to raise defects with the seller;
• the water company, if the problem looks like it is in a shared drain or public sewer.

Ask for the footage, not just the summary, and keep it.

What high-pressure jetting is

A jetter pumps water at high pressure through a hose with a special nozzle. The nozzle pulls itself along the pipe and blasts away fat, scale, silt and small roots. It is often used to clear a stubborn blockage, to clean a drain before a camera survey, or after a survey has shown build-up.

Jetting is effective but it is not gentle. On a pipe that is already cracked or has displaced joints, it can make things worse. That is one reason a survey before jetting is often sensible, and why it should be done by someone who knows what they are looking at.

We do not give a method for jetting a drain yourself. Hire jetters and pressure washer drain kits exist, but high-pressure water can cause injury and can damage pipes, and the work usually means opening chambers. Leave it to a drainage firm.

Do not enter a chamber

Do not enter a chamber. Inspection chambers and manholes can contain harmful gases and low oxygen, and the sides and steps may be unsafe. Drainage firms work from the surface wherever they can and follow their own safety procedures where entry is needed. Inspection chambers and manholes explains when it is reasonable to lift a light private cover to look, and when to leave it alone.

Choosing a drainage firm

• Ask whether the survey includes a written report and the footage, and in what format.
• Ask whether they will jet before or after the survey, and why.
• Ask them to show you the defects on the footage and point out where they are on the ground.
• Get repair recommendations in writing, with the options: patch repair, relining or excavation.
• Get more than one quote for any major repair, using the same survey.
• Check who they think owns the drain before you pay for repairs, and contact the water company if it may be theirs.

Be wary of a firm that finds a serious defect but will not show you the footage, or presses for an immediate expensive repair. Hiring a plumber covers references, written quotes and payment.

Do I need a CCTV drain survey when buying a house?

It is not required, but many buyers of older houses, or houses with big trees nearby, choose one. It can find problems that would otherwise appear after you move in.

Can jetting damage drains?

It can, especially pipes that are already cracked or have moved joints. An experienced firm will judge the pressure and nozzle for the pipe, and a survey first helps.

Who pays for a drain survey if the problem is in the public sewer?

Usually the person who orders it. If the survey shows the defect is in a public sewer, contact the water company with the report. Whether it refunds anything is up to it.