A home buyers drain survey is a check you can do on a property before buying. It’s an in-depth look at the drains – the underground pipes that take water and sewage away from the home. You don’t need to do one (unless your lender insists), but it can help flag potential issues with pipework, drainage, infestations, or your property’s structure.

Drain surveys aren’t usually included in a standard home buyers survey – the general “property health check” potential buyers do before moving in. But your mortgage provider might ask you to get one done before they give you a mortgage. 

Just like a standard survey, if you do one, it usually happens after your offer has been accepted but before you sign anything. That way, you’ve got time to back out of the sale (or renegotiate your offer) if it uncovers anything serious.

So, here’s everything you need to know about home buyers drain surveys – from what they involve to why it might be a good idea to do one.

What does a drainage survey involve?

A drain survey is a thorough inspection of the pipes connecting a property to the water network (also known as the drainage system). 

Every house with running water has a drain system, but they’re hidden away underground, out of sight. Unless there’s a serious issue – like flooding or a bug infestation – you won’t usually give your drains a second thought. But before buying a house, it can be a good idea to make sure everything works as it should.

That’s precisely what drainage surveys are for. Drain surveyors – the engineers who do the survey – will use CCTV equipment to take a deep dive into your drains.

They will look for two things: potential problems and the size of your drainage system.

1. Drainage problems

The most important part of a drain survey will be the hunt for potential drainage problems, such as:

• Pipe blockages
• Broken or leaky pipes
• Tree root incursions – which can crack or block pipes
• Pest infestations, like rats
• Poorly connected pipes (it’s the homeowner’s responsibility to make sure the right pipes are connected to the right networks in the right way)
• Pitch fibre pipes (pipes from the fifties made with a mix of tar and natural fibres. They tend to need replacing after about 40 years)
• Other faults in the property’s drainage system

While none of these might be a problem now, they could become problems in the future. Drain surveys make sure everything’s working as it should before you sign on the dotted line.

2. Your drainage system

As part of the survey, drain surveyors will usually give you a map or plan of your drains, so you can see where your drains connect to the national water network. 

This might not grab you as the most interesting document in the world, but it can be a handy way to clarify your legal responsibilities as a homeowner. 

For example, if there’s a problem with the drainage in the future, this plan can tell you if it’s your job to fix it, a neighbour’s, or your water supplier.

Do I need a drainage survey?

Here’s the thing: you don’t need to do a home buyer drain survey. So, it could be tempting to simply avoid the extra expense, particularly as you’ve already had your offer accepted. But:

• Mortgage lenders might ask you to do a pre-purchase survey before they give you a mortgage.
• Surveyors and conveyancers often suggest you do a drain survey on top of the standard house buyers survey.

Ultimately, it’s your call whether to do a drain survey – and there are a few pretty good reasons to get one:

Benefits of a drain survey

• You may be able to renegotiate the house price. Say the drain survey flags up £3,000 of repairs. You might not want to pay this on top of the cost of the house. Professional drain surveys can support your case for negotiating a lower price for the property.
  
• Avoid nasty surprises in the future. Drain surveys give you a better idea of the property’s condition upfront, and flag any problems that may need attention in the future.
  
• Get clarity on what you own and what’s your responsibility. This can help if any problems come up later. And, if you plan some renovations in the future, it can be helpful to know where the drains are.
  
• Get insured. Sometimes, home insurance companies ask you to do a drainage survey before they cover your property. Doing one before you buy saves you the hassle later on.
  
• Ultimately, you know what you’re buying. Worst-case scenario: you can pull out of the purchase if there are serious problems. It’s always better to know in advance.

What to expect from a drain survey

Home buyers drainage surveys are done before you move in, but after the seller has accepted your offer. That means it’s one of the final stages of your house buying journey – just before you finalise the contracts.

Here’s how the whole process works:

1. Find a drain surveyor

Potential buyers tend to get a drain survey done by one of two people: 

• A chartered surveyor. The people doing your general home survey may be able to provide you with a drain survey too. 
• A specialist drain surveyor. These are expert engineers specialising in drains. Your surveyor may recommend one if they can’t do it themselves, but you may have to shop around.

How much does a drain survey cost? Depending on your area, and the size of your property and any land that comes with it, a home buyers drain survey can range between £100 and £400. It’s best to get a few quotes before choosing a surveyor.

2. Do the survey

It can feel like an extra hassle to have to organise yet another survey when you have quite a lot on your plate already. But a drain survey should only take between one and two hours.

3. Get the results

At the end of your drainage survey, you’ll typically get three things:

• A “health check” report. That’s the details of any problems the drainage system has, like leaks, infestations, or collapsed pipes.
• An ownership report, which will tell you where your pipes are and which ones are your responsibility.
• A CCTV recording. Sometimes, insurers and mortgage lenders can be interested in having proof of the condition of your drains. CCTV recordings can let you see for yourself what’s going on down there.

If your lender has requested that you do a drain survey, it’s worth asking them what they would like to see. 

4. Next steps

Armed with the results, you’ll have a better idea of the condition of the property. 

If everything is in fine working order, it can give you extra peace of mind before you complete the purchase. 

If not, you have a few options. Depending on the condition of the drains, you could get them fixed at your own expense, renegotiate the price of the property, or walk away from the deal. 

Buying a home? Try Habito Plus

There can be a lot to think about when buying a home. At Habito, we offer full support throughout the entire process, from finding the right lender to getting a detailed survey on the property. 

Take the hassle out of buying a home with Habito Plus.