Why you should consider a pre-purchase drain inspection

Moving home can stretch you financially, and it’s even worse for first-time buyers, who typically have less cash to play around with after moving in. No one wants unexpected maintenance problems, and that’s why it’s worth getting a pre-purchase drain inspection. It highlights drainage problems before you buy, removing the surprise of costly repairs.

We often speak with new house buyers faced with extensive drainage repairs just months after moving home. Had they arranged for a pre-purchase drain inspection beforehand, they’d have been able to discuss the findings with the seller. They could even have negotiated the cost of repairs off the sale price if there wasn’t time for the vendor to fix the problem.

Some people refer to it as a “pre-purchase drain survey”, while others call it a “home-buyer’s drain survey”. What sets this apart from a CCTV drain inspection, which is typically done to identify and fix a problem, is the mapping of the drain network.

The process involves feeding a high-resolution camera into the system through a nearby access point, such as a manhole or inspection chamber. The process is controlled by a drainage engineer above ground, who feeds the camera through the system – noting any defects, their location, and their size.

Tip: It’s not just people buying a house who stand to benefit. Vendors may want to fix drainage issues at their own expense, speeding up the conveyancing process, and maximising the property’s value at point of sale.

The homebuyer’s survey only gives you an overview of the property’s condition, with a valuation and cost of reinstatement. It’s purely a visual inspection that notes obvious defects, then advises on the repairs needed. The surveyor will check:

• Roofing (from inside and ground level)
• Walls and ceilings
• Doors and windows
• Lighting and heating
• Insulation and damp-proofing
• Woodwork (for rot or infestation)
• Structural issues (e.g. subsidence)

The surveyor won’t check the drains. In fact, they’ll likely recommend that you get a drain inspection. That’s because it’s a specialised service that requires a drainage engineer with the right equipment.

A pre-purchase drain inspection outlines useful information:

1. How the drains are used and where they connect to sewer lines
2. What the pipes are made of, their size, and their overall condition
3. Whether there’s a build-up of grease or fatty deposits
4. If there’s a build-up of scale, which can lead to a blockage or corrosion
5. Whether there are any damaged, broken or misaligned joints
6. If tree roots have entered the system, such as through a leaky pipe
7. If any drains have collapsed, which can occur due to long-term neglect

With this information, the engineer will report their findings to you. If they uncover the need for remedial work, they’ll give you their recommendations. It’s then up to you to decide whether or not you want to go ahead with the repairs.

Detailed reporting gives everyone involved in the home-buying process something to refer to. The report displays structural data found during the survey, and includes the start and end point of the drains checked, the depth of the pipe run, and the position and nature of any faults discovered. It features time-stamped images, and you’ll also receive a video. A comprehensive survey may include web links, drawn diagrams, and will likely be tailored to your requirements.

These reports are often used by conveyancing solicitors, waste water service providers (e.g. Thames Water), and architects and builders before starting a construction project. Insurance companies may also want to see the report if you try to claim on wastewater issues.

Tip: Some engineers might begin the inspection, but stop when they find a problem. They’ll then charge for another survey once it’s rectified. Look for someone that can fix your drains and check their work without making you pay for two entirely separate surveys.

Would you like to see what a report looks like? We have a sample below ready to view.

Drain Survey Sample

A drain mapping survey includes all elements from the standard CCTV drain survey, and is sometimes known as ‘drain tracing’ or ‘asset mapping’. It’s a highly recommended part of the pre-purchase drain survey. The completed map serves as an aerial view or diagram of the drainage system. It determines:

• The position of waste and rainwater pipes
• The directional flow of wastewater
• The placement of gullies and connections
• The depth and diameter of each pipe run
• The location of drain access points

Tip: A drain map will show the layout of your drainage system. This can make it easier for an engineer to pinpoint future drainage issues, helping save time and keep costs down.

Having a pre-purchase drain inspection from the outset can help with future extension projects. If you don’t have one, then you’ll likely need a “pre-build” or “pre-conditional” survey to clarify drain ownership. If your planned extension sits within three metres of drainage and sewage systems owned by the local water authority, then you may run into trouble. If this happens, you’ll need to apply for a build-over agreement, which ensures two things:

1. The local water authority can still gain easy access
2. Your extension won’t impact their drainage system

Tip: By arranging a pre-purchase survey before buying a home, you have this information ready for when you need it. You can then supply the report to your building surveyor or construction firm when the time comes.

Building an extension means you’ll need a post-conditional inspection too. This happens once the drainage system is changed to accommodate the extension, and checks for compliance with Part H of the Building Regulations.

They aren’t a legal requirement for new buyers or existing homeowners, but a surveyor would never discourage one. Standard property surveys don’t offer a detailed look into the drainage systems, and some lenders will ask for a pre-purchase drain inspection before approving your mortgage.

Tip: Insurance companies tend to expect a report for all drains you try to claim on. Having a pre-purchase drain inspection makes them more likely to accept a future claim, and you may even get a better rate.

The time it takes to carry out a survey depends on the size of your drainage system. Surveys for small, terraced homes are usually quicker than they are for larger, detached homes. That said, no one can say for sure until a drainage engineer begins the inspection.

A property with three manholes would take up to three hours to survey, plus any additional time for reporting. That said, be aware that finding and resolving a problem would naturally slow the process down.

Your engineer will usually share the results with you on the same day as the inspection.

We charge £250 plus VAT for a CCTV drain inspection without a map, and some people are happy with this as a pre-purchase drain inspection. However, we recommend getting a CCTV drain mapping survey, which costs £350 plus VAT. These prices apply to properties with up to and including four manholes/access chambers, which covers most residential properties in London and the Home Counties. We’d expect only very large, detached houses to have more. Costs would increase by £75 plus VAT for each additional manhole.

Whether you need assurances before buying a property, or simply have a blocked drain, Aspect is ready to help. We can inspect your drains and pipes, and provide drain repair services using the industry’s most reliable methods.