How do I find the drainage plans for my house?

If you’re in need of looking into the draining plans for your house, the short answer is to start with your water company’s public sewer map. Most now let you view this free online, or you can request an official Asset Location Plan for a small fee. That covers the public network. A CON29DW can include an extract of the public sewer map and useful information about the property’s drainage and water connections to help with your search.

If none of those turn anything up, ASL Limited can survey your property and draw you up an accurate, current plan. Sometimes even a simple drainage survey can be useful when selling a property or the requirement to investigate private drains by inspecting the chambers and carrying out a CCTV survey

You don’t always have to carry out the main drain connection immediately.

In some cases, simply investigating the route, taking levels and producing a practical plan showing that a connection to the public sewer is possible can be valuable information for the homeowner. It can remove some of the uncertainty for a future buyer and may add to the property’s appeal or value, particularly where the property currently relies on a septic tank, cesspit or treatment plant.

ASL can look at the existing drainage, use a probe where appropriate to help identify the route of underground drains, take relevant levels and produce a rough sketch showing a possible route towards the public sewer.

This does not mean the connection has been approved, but it can give the homeowner or a future buyer useful evidence that a mains drainage connection appears possible and is worth taking to the next stage.

Get in touch: Call 0800 181684

Why would I need a drainage plan?

Every home sits on top of a network of drains, and knowing where they run, who’s responsible for them, and where they can be accessed matters more often than most homeowners expect. A drainage plan tends to become essential if you’re:

• Extending your property and needing to apply for a “build-over agreement”
• Trying to locate a collapsed or damaged drain
• Applying for an Environment Permit or consent to discharge into a watercourse
• Buying or selling a property, since drainage condition and layout can factor directly into price negotiations, especially if a private system isn’t working properly or doesn’t meet current regulations

If you’re selling a property with a private drainage system (a septic tank or treatment plant), you’re legally required to give this information to the buyer.

If the drainage plan you have is old, or you’re not confident it’s still accurate, it’s worth getting a comprehensive drainage survey done and a new plan drawn up.

Where Can I Get a Copy of the Public Sewer Map?

Your local water company (Thames Water, for example, if you’re in Surrey or the surrounding area) holds the plans for the public network. Many companies now let you view an interactive public sewer map online for free. If you need something more formal, you can request an official “Asset Location Plan” in writing, and you may be charged a fee for this, though not always.

One thing to keep in mind. These plans show you the public sewers, the parts owned and maintained by the water company. However, they generally won’t show you anything about your own private drainage.

Can the Council Give Me My Drainage Plans?

Sometimes. If your house is a new build, the drainage plans may have been submitted to the council as part of the build. Older properties may also have plans on file if a drainage plan was ever included in a past planning application, in which case it can sometimes be pulled from the archives.

Two things worth knowing before you go down this route. Councils often charge an administration fee for searching old property records, and there’s no guarantee the plan on file still matches what’s actually there. Extensions, repairs and other changes made since the original submission won’t be reflected.

Can I Get Drainage Plans Through a Property Search or Solicitor?

If you bought the property through a standard conveyancing process, there’s a good chance this already exists. Solicitors typically order a CON29DW drainage and water search as part of the purchase, and this includes details of the public sewer connections along with an extract of the sewer map for that address. If you still have your purchase paperwork, it’s worth checking there first as it can save you a call to the council or water company entirely.

Can I Ask the Previous Owner for the Drainage Plan?

If the previous owner had drainage plans drawn up, whether for a planning application, building control, or their own peace of mind, they may still have a copy. If you’re mid-purchase and in contact with the seller, or you know the previous owners some other way, it’s a straightforward thing to ask for.

Can My Neighbours Help If I’m on a Shared Drainage System?

If your property shares a private drainage system with neighbouring homes, they may hold plans that cover your section too. On a private road, a residents’ association is sometimes the quickest way to find out if plans exist anywhere at all.

Do I Have to Register a Private Drainage Plan Anywhere?

No. There’s no official, central record of private drainage in the UK, which is a big part of why tracking one down can be so difficult in the first place. If a drainage plan was drawn up by a professional company like ASL, or by an architect, there’s no obligation to submit it anywhere officially, with one exception: if you’re selling a property with a septic tank, treatment plant or cesspit, you’re required to show the buyer where it is and how it should be maintained.

What Should a Drainage Plan Include?

A proper drainage plan should show your property’s general layout along with every drain on the land, clearly marking surface water drains separately from foul water drains. If you’ve got other drainage features, effluent tanks, storage areas, anything like that, those should be marked too. Depending on your property, a full plan might also include:

• The layout of the drainage, including access points
• Private systems: septic tanks, treatment plants and cesspits
• The location, depth and construction details of any soakaways (where accessible)
• Discharge points from the site
• Invert levels of the inspection chambers
• Pipework diameter and material

If your home was designed by an architect, the drainage plans were likely part of the original design package, and the development company may still hold a copy. If nothing like that exists for your property, that’s exactly what ASL’s drain mapping service is for. Providing a clear, accurate picture of your drainage, built from scratch if it needs to be.

What If There’s No Drainage Plan for My House at All?

It happens more often than you’d think, particularly with older properties or homes on private drainage. If every avenue above comes up empty, the most reliable option is a drain mapping survey. ASL’s engineers can trace and record your full drainage layout and produce a plan you can actually rely on, for a build over agreement, a house sale, or just your own records.

Call our team on 0800 181684 for a quote, or get in touch online.

If your property shares a private drainage system with neighbouring homes, they may hold plans that cover your section too. On a private road, a residents’ association is sometimes the quickest way to find out if plans exist anywhere at all..

FAQS

Do I have to pay for public sewer plans?

Sometimes. Many water companies now offer free online viewing of the public sewer map. A formal, written Asset Location Plan often comes with a small fee.

Will my council definitely have my drainage plans?

No. Councils only hold drainage plans if they were submitted as part of a new build or a past planning application, and even then, older changes to the property may not be reflected.

Do I have to register my private drainage plan with anyone?

No, private drainage isn’t centrally recorded in the UK. The only exception is when selling a property with a septic tank, treatment plant or cesspit, where you’re legally required to disclose its location and maintenance needs to the buyer.

What’s the fastest way to get an accurate drainage plan if nothing exists?

A professional drain mapping survey. ASL can trace and map your full system and produce a plan you can rely on, rather than relying on old or incomplete records.

Related Reading

Take a look at our article on the five benefits of proactively having drain mapping carried out. https://www.asllimited.co.uk/drainage-blog/5-benefits-proactively-having-drain-mapping-carried-out-cctv

Looking to have a sewage treatment plant installed? Here’s some essential information you need to know first. https://www.asllimited.co.uk/drainage-blog/sewage-treatment-plant-installation-essential-information 

Drainage and waste removal from any building is essential, whether it’s wastewater or rainwater, and to achieve this safely and efficiently, some rules and regulations must be followed. Here’s what you need to know. https://www.asllimited.co.uk/drainage-blog/drainage-building-regulations-and-what-you-need-know