Do I Need a Drain Survey When Buying a House?

You don't legally need a drain survey to buy a house, but it is often worth having one. A standard house survey rarely looks inside underground pipes, so cracks, roots, displaced joints and collapses can go unnoticed until after you move in. A CCTV drain survey before you exchange contracts shows the condition of the drains and gives you evidence to negotiate.

This guide explains what a normal survey and the conveyancing searches cover, when a drain survey is most worthwhile, what it costs and how to use the results.

Does a normal house survey check the drains?

Usually not in any detail. A standard building survey may lift accessible inspection covers and note what the surveyor can see, such as standing water or debris in a chamber. It doesn't normally include a camera inspection of the underground pipes, which is where most expensive drainage defects are found.

Your solicitor's drainage and water search, often called a CON29DW, comes from the water company. It tells you whether the property is connected to the public sewer and whether any public sewers are recorded within the boundary. It is useful, but it says nothing about the condition of the pipes.

So neither the survey nor the searches tell you whether the drain under the garden is cracked, full of roots or partly collapsed. A CCTV survey does.

When is a drain survey most worth having?

A pre-purchase survey is especially worthwhile if any of these apply:

• The house is older. Clay pipes laid decades ago can crack, and joints can move with the ground.
• It was built between the 1950s and 1970s. The Financial Ombudsman Service describes pitch fibre pipes, "wood cellulose impregnated with tar", as popular in that period and notes that many insurance policies don't cover them.
• There are large trees near the drain runs. Roots find their way into cracks and open joints.
• There is an extension, conservatory or garage near a drain. Structures built over or close to drains can damage them, and may have needed the water company's approval.
• You have seen warning signs at a viewing: smells, slow drains, damp patches, sunken paving or overflowing gullies. See our guide to the signs of a blocked or collapsed drain.
• Your lender or insurer asks for one. MyJobQuote notes that drain surveys are often required by lenders or insurers on older homes.

What if the house isn't on mains drainage?

Rural homes may drain to a septic tank or treatment plant instead of the public sewer. The Environment Agency's general binding rules say a septic tank must not discharge directly to a watercourse, and when a property with one is sold, the buyer and seller should agree who pays for the upgrade. Ask the seller for the tank's details and emptying records, and have the system checked before you commit.

Why do extensions over drains matter?

Building close to a sewer is controlled. Part H4 of Approved Document H applies to building work within 3 metres of the centreline of a sewer or drain shown on the sewer records.

Across Nottinghamshire and most of Derbyshire and Leicestershire, the sewerage company is Severn Trent. Its building over sewers guidance explains two routes:

Severn Trent also asks owners to contact it early if the sewer is 300 mm or larger. If the house you are buying has an extension near a shared pipe, ask the seller for evidence that the correct approval was obtained. A CCTV survey will show whether the pipe under or beside the extension is in good condition. Since the 2011 transfer, pipes shared with neighbours are usually public sewers, so this affects far more homes than people expect.

What does a homebuyer drain survey show?

A camera is passed through each accessible drain run, usually from inspection chambers, and the footage is recorded. The report should show:

• a plan of the drain runs and where they connect;
• the pipe material and size;
• each defect with its distance along the pipe, a standard code and a grade;
• photos of significant defects;
• recommendations, separating essential repairs from minor issues.

Our guide to what a CCTV drain survey report shows explains the codes and grades in detail.

How much does a homebuyer drain survey cost?

National price guides give these typical ranges:

These are market ranges, not quotes. The price depends on the number and length of runs, access, whether the drains need clearing before the camera can see, and the level of report you need. MyJobQuote also puts pre-survey jetting at £100 to £150 where it is needed.

Compare that with the cost of putting things right after you move in. MyBuilder puts drain relining at roughly £70 to £250 per metre. MyJobQuote puts excavation and replacement at £250 to £650 per metre, a typical collapsed-drain repair at around £850 and a fully collapsed drain at £1,000 to £3,000.

How do I use the results?

If the report is clear, you have peace of mind and a baseline record of the drains. If it finds problems, you have options:

1. Get a repair quote based on the report, so you know the likely cost.
2. Ask your solicitor to raise it with the seller. You might ask for a price reduction, a repair before completion, or a retention.
3. Check responsibility. A defect in a shared pipe or beyond the boundary is usually the water company's responsibility, not the owner's, so it may not affect the price at all.
4. Speak to your insurer before you buy if pitch fibre or existing damage is found, because it may affect cover.
5. Keep the report. It is useful evidence if problems appear later.

Book the survey early. You will need the seller's permission for access, and the report should arrive before you exchange contracts.

When to call a professional

If you are buying an older home, a home with trees or extensions near the drains, or anywhere you noticed warning signs, book a survey before you commit. Urgent Drainage Solutions carries out homebuyer drain surveys across Nottinghamshire, Derbyshire, Leicestershire and Lincolnshire. Our CCTV drain surveys start from £120 + VAT for up to 100 m of accessible runs, with a written report coded to WRc MSCC5, and we explain the findings in plain English so you can talk to your solicitor with confidence.

There is no call-out fee and the price is agreed before we start. See our prices, book online or call 07300 600 950.

Sources

• Approved Document H: drainage and waste disposal (gov.uk)
• Severn Trent: building over sewers
• Environment Agency: general binding rules for small sewage discharges to surface water
• Financial Ombudsman Service: home insurance and drains
• MyJobQuote: drain survey cost
• MyJobQuote: cost to repair a drain line breakage
• MyBuilder: drain relining cost