Build over or near to a public sewer

Are you considering building a new property, extending, or renovating an existing one? We’re sure you’re excited and possibly a little daunted too. To help your project be a success, we’ll explain why considering any nearby sewers is important at this stage, how to apply for any permission you need and what happens next.

Building an extension can impact the public sewer network serving you and your neighbours’ properties. That’s why you’ll need to submit a build over application if you’re planning to build within three metres of a public sewer.

You may wonder why you need permission, especially if the sewer is within your land.

Here are a few crucial reasons you need our permission:

• It helps to prevent damage to the sewer – Unless the sewers are considered, they could collapse under the weight of any new structures. This could damage your property, interrupt drainage for other properties and increase the likelihood of flooding. Reviewing your application allows us to check the necessary precautions are in place early on and ensure the sewer is in good structural condition before you impede future repair access.
• We need constant access to our network – We’ll check your plans will continue to allow us 24-hour access to all public sewers and manholes to carry out routine inspections, maintenance, and repairs, which are essential to help us protect your home and our pipes.
• You’ll need the correct paperwork – Before a building control surveyor will give you a completion certificate or ‘sign off’ your works, they’ll expect to see our permission for the build over/near taking place. If you sell your property in the future, the buyer’s solicitor may ask for a copy of the Build Over Agreement showing our permission for the building works too. Without this, selling your property could become more complicated.

The good news is if you’re aware of the guidance early on you can plan your building works with the sewer pipe included early in the design process. The information below will explain what you need to consider, including how to determine whether you need to make an application, helpful diagrams, and answers to frequently asked questions.

Because each application and design proposal we receive is unique, approval is given on a case-by-case basis. But we’re here to give you the guidance and support you need to progress your application.

Before you apply

Cases when you will not need a build over or near application

1. If you are constructing a new extension, first you should check if it is subject to the Building Regulations. If it is, then you are required to confirm that it meets the standards set out in section H4 of the Building Regulations and this can be assessed by a Local Authority Building Control (LABC) department or an independent approved inspector as per your choice.

Some LABCs or inspectors may be able to progress your proposals in consultation with us, rather than submitting a build over application to us.

• Pipe size is 225mm or less
• Pipe depth is less than 3m
• The total length of the public sewer built over is less than 6m
• Access to the public sewer is unimpeded and you’re not building boundary to boundary (within 1m of property line).
• It’s an extension not a new detached structure
• Building over/near only one public sewer

Building proposals that we do not accept

There are situations where we never allow the building over or near to of our sewers. These include:

• Building over or near to public water mains, pumped or rising mains, vacuum mains and strategic or ‘trunk’ sewers
• Building over or near to existing sewers on new development sites or re-development sites. Instead, you can look to divert the sewer, or to save cost, modify your plans so that your building is at least 3 metres from the sewer
• Where there would be an internal manhole or change in pipe direction (i.e. Y-connection or a junction of a public sewer) within the proposed building. These are not allowed due to potential odour and flooding issues. We will need to have access to the sewer. You’ll need to relocate these outside the property to get approval
• If there are easements or restrictive covenants on the pipework by your proposed works, you won’t be allowed to build near or over the pipework
• The pad, raft and cantilever foundation types over the public sewer are not permitted as it can impact our future access to repair the adjacent public sewer and significantly increase the risk of damage to the structure during repair works. We also do not permit reinforced concrete floor slabs over public sewers for the same reason
• If you have Boundary-to-Boundary infill structure, where there are already structures both sides of boundary impeding future maintenance and repair access to the public sewer
  

Build over or near to a sewer application routes

When you apply to us there are two routes your application can take depending on your design:

• Build Over Self-Declaration
• Build Over Formal Approval Application (with/without Sewer Protection Agreement)

The two applications differ in costs and follow different process. The quick reference guide is designed to help you understand what route your application will take with reference to certain circumstances. It details whether it will be a Build Over Self-Declaration, an approved Build Over Formal Approval Application, an approved build over with a sewer protection agreement, or where the building project proposal won’t be acceptable.

In some cases, we may decide to turn your Build Over Self-Declaration into a Build Over Formal Approval Application, upon review where additional cost will be required.

Locating the sewer around your property

Before starting any construction works, you will need to locate any public sewers to confirm whether you are building within 3 metres. Once any sewers are located you will need to determine the sewer ownership, identify the sewer size, depth, and pipe material.

You can request an indicative sewer or water map online, that will help with your investigation.

Due to recent changes in legislation, our maps may not always show all public sewers. If available, we only hold records for public assets, so any private pipework will not be shown. If there are no sewers showed on the map around your property, you will need to arrange a CCTV survey or careful excavation. Alternatively, you can apply for a Build Over Formal Approval Application, and we will do all necessary investigation for you.

Here are more details on what you will need and how it all works for each application route.

Utility Crossings

If you are installing a new utility cable, pipe, or duct such as a high voltage electrical cable that will need to cross a public sewer you will need to submit a buildover/close-to application. This application will require a CCTV survey with sonde location to confirm the exact position and depth of the sewer you are proposing to cross.

For more information about Utility Crossing & Locations, see our technical guide.

Making an application

Build Over Self-Declaration

Building over one public sewer, where the total length of sewer built over is less than 6m, the sewer to be built over is a non-critical public sewer with an internal diameter of 225mm or less, sewer is less than 3m deep, and not a boundary-to-boundary extension, then it’s likely it can be progressed under a self-certified build over approval known as a Build Over Self-Declaration. As part of the application process, we ask all applicants to complete a list of questions to determine if you meet criteria.

Steps we'll take to help with your project

Don't worry we'll be in touch along the way to make sure everything goes smoothly.

Fill in our online form, submit your required documents and pay a fee for the self declaration. We’ll review your application within 5 days and let you know if we have everything we need to progress.

We will do a review and send you a conditional approval letter within the next two weeks. This conformation will need to be shared with your builder. If you are relocating a manhole chamber or undertaking minor pipe repairs, you will need to pay an inspection fee of £84.

Step 1 – You apply online and pay a fee

Fill in our online application using our GetConnected portal . We’ll ask some questions to determine if you can self-certify through a Build Over Self-Declaration. If you are unable to meet the self-certification points, or if you are unsure regarding some of the questions, we’ll automatically transfer the application to a Build- over/near-to Formal Approval Application at an additional fee.

You will need to pay an application fee:

• The Build Over Self-Declaration of Works fee of £102.00 (incl. 20% VAT)

You will need to include the following with your application:

• An existing and proposed site plan (.pdf) (1:100 or larger clearly showing the location of sewers and manholes)
• A site location plan (.pdf) (1:1250 or larger).
• A cross section foundation design (.pdf) (1:100 or larger).
• Copies of all drawings submitted for building regulations approval.

Frequently Asked Questions

Step 2 – We send you a conditional approval letter

If you meet the criteria and can self-certify through a Build Over Self-Declaration, we’ll provide a conditional approval letter to build over our assets within 10 working days.

If you are relocating a manhole chamber or undertaking minor pipe repairs, you will need an inspection to be carried out. The inspection fee is £84 (inc. 20%VAT). Don’t worry, your response letter will state whether this is needed or not. If so, you will be asked to pay a fee using BACS transfer or card payment over the phone.

You will need to request an inspection by contacting your Adoption Manager (contact details will be advised in the letter). Please note that a minimum of 48 hours’ notice will be required for an Adoption Manager’s visit and any new pipework and connections should be left exposed and not backfilled so that they can be viewed. Please ensure the open trench is adequately supported to ensure it does not collapse, as you will be liable for any damages to the public sewer. If you are not relocating a manhole the inspection will not be needed.

Frequently Asked Questions

Build over or near a sewer Formal Approval Application

If your application answers do not meet the Build Over Self-Declaration criteria, your application will automatically progress to a Build Over Formal Approval Application.

We’ll technically assess your proposal to determine that it adequately protects the public sewer and our future access to maintain it. We’ll suggest any changes or conditions that will need to be made to assist you in progressing your application to the approval stage (if required).

It is possible that you have applied for a Build Over Self-Declaration, however upon review we found that it does not meet the Self-Declaration criteria. In this case, we will switch your application to the Build over Agreement application. You won’t need to reapply, but you will need to make payment using BACS or a card payment over the phone to cover the additional fee for the application and CCTV survey (if applicable).

For some sites we may also ask you to complete a Sewer Protection Agreement (SPA) with us to ensure the protection of access for any future maintenance and repairs of the stretch of sewer being built over. This will be clearly identified in our conditional approval letter and the reason it is required.

Steps we'll take to help with your project

Don't worry we'll be in touch along the way to make sure everything goes smoothly.

Fill in our online form and pay application fee. We’ll review your application and let you know if we have any questions within 5 days.

We will carry out a CCTV survey within 20 days to determine the condition and exact location of the affected sewer. You have an option to provide/carry out your own CCTV survey.

If you are relocating manhole chamber or undertaking minor pipe repairs, you will need an inspection. We will let you know if this is needed in our conditional approval letter.

If you are relocating a manhole chamber or undertaking minor pipework repairs, you will need an inspection. We will let you know if this is needed in our conditional approval letter.

We will send you a Build Over Agreement letter within 7 days, permitting you to proceed with your building works.

Step 1 – You apply online and pay your fee

Fill in our online application using our GetConnected portal . Based on your online application answers, you will be directed to the Build Over Formal Approval Application, if you are not meeting the Build Over Self-Declaration criteria.

You will need to pay an application fee:

• An application fee for a Build Over of £720.00 (incl. 20% VAT). The fee is including a CCTV survey. If you have your own CCTV survey, which meets our criteria, share your CCTV survey when submitting your application and we will refund you £200.

You will need to include the following documents with your application:

• An existing and proposed site plan (.pdf) (1:100 or larger clearly showing the location of sewers and manholes).
• A site location plan (.pdf) (1:1250 or larger).
• A cross section foundation design (.pdf) (1:100 or larger).
• Copies of all drawings submitted for building regulations approval.
• CCTV plan (if available, which includes sonde tracing, dated within the last 6 months)

We’ll review your application within 5 days and let you know if we have everything we need to progress.

Frequently Asked Questions

Step 2 – We carry out a CCTV survey

As part of the Build Over process to determine the condition and actual location of the sewer, we will need to carry out a CCTV survey. The survey will trace the line of the sewer and show the condition of the pipe. Our CCTV contractor InSewer will be in contact with you to arrange a mutually convenient time to visit. Once the survey is complete you will be provided with the CCTV plan (full report is not included in this service), which will be included in the conditional approval.

If you carry out and provide your own CCTV survey it must be:

• dated within 6 months
• include a detailed (.pdf) report and site photos
• include a supporting plan showing dimension, layout of manholes and position of sewers

Please submit this with your application and if it meets our requirements, we’ll refund that part of your application fee of £200 in line with what it would have cost us to undertake the survey ourselves. Also, if the CCTV is not required, we will refund you.

Top: Pipe in good condition, no cracks, water flowing freely.

Bottom: Pipe in poor condition with fracture, longitudinal crack and collapsed section ahead.

If you are providing your own CCTV plan, please check an example below to make sure your plan has all information that we need.

Frequently Asked Questions

Step 3 – We send you our conditional approval

We will send you our conditional approval letter, setting out any conditions required to be followed for your proposals, within 8 working days after we receive the CCTV survey report for your property. For most properties, this happens within 20 working days from when we received a complete application.

For some sites we may also ask you to complete a Sewer Protection Agreement with us to ensure the protection and future maintenance and access of the sewer. We will advise if the Sewer Protection Agreement is needed in our response letter.

Frequently Asked Questions

Step 4 – You book an inspection

If you are relocating a manhole chamber or undertaking minor pipe repairs, you will need an inspection. Your conditional approval letter will state whether this is needed or not.

You will need to contact our Adoption Manager (contact details will be provided in the conditional approval letter). Please note that a minimum of 48 hours’ notice will be required for an Adoption Manager’s visit and any new pipe work and connections should be left exposed and not backfilled so that they can be viewed by the Adoption Manager. If you are not relocating a manhole the inspection will not be needed.

Step 5 – We send you a Build Over Agreement

We will send you a Build Over Agreement letter within 7 days, permitting you to proceed with your building works.

Frequently Asked Questions

Still have questions? We are here to help

We understand that all projects are different, and it might be hard to understand what the right and most cost-effective option is. Please visit our Frequently Asked Questions page for more guidance or simply request a call back from our helpful team.

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