Diversions and Disconnections
If you have an existing Severn Trent water main or sewer on your site you may need to apply to for it to be diverted. In some circumstances we can give permission for you to build close to or over a public sewer.
Sewer Diversions
Under Section 185 of the Water Industry Act 1991, any person with an interest in that land or adjacent land may request that the undertaker alter or remove a sewer if it is necessary to enable person to carry out a proposed improvement of the land in which they have an interest.
Severn Trent will allow a builder or developer to undertake a diversion themselves if the works are considered low risk and are entirely within the land under the ownership of the party applying for the diversion or within a public highway.
Where a diversion falls outside of land owned by the applicant or is considered a higher risk, Severn Trent will undertake the works ourselves.
New development affecting a public sewer on your land
If you have identified a public sewer on your land which is owned by Severn Trent and your new development affects it by having properties proposed over them or within 2.5m (for sewers less than 300mm in diameter) or 5m (for 300mm diameter sewers and above) you will need to apply for it to be diverted. You can find our records on https://utilities.digdat.co.uk/ which will allow you to confirm if any existing sewers are within your land.
Due to a change in legislation on 1 October 2011, there may be former private sewers on the site which have transferred to Severn Trent, but which are not shown on the statutory sewer records. These sewers are now public sewers and would also have protective strips that we will not allow to be built over or within.
This is only for sewers that were connected before 1st July 2011 any private sewers constructed after this date will remain private. It is your responsibility to identify these sewers, however, if you are unsure please feel free to contact us at Asset.Protection@severntrent.co.uk providing any information you have on its location and what the asset serves and we will help confirm if they are now our assets.
If you have a public sewer on your site and are making changes to an existing domestic property that would impact the sewer e.g. building an extension, we may in some cases give you permission to build over it. Find out more about this by visiting our build over sewers page.
There are many steps to the process so please read through the below to ensure you understand what is required for an acceptable design and to satisfy the requirements laid out under the diversion agreement.
Application Process
There are many steps to the process so please read through the below to ensure you understand what information and plans are required to achieve an acceptable design and to satisfy the requirement for a diversion agreement.
When we receive the application, it will be checked to ensure all required information has been received. If information is missing, we will contact you and the application will be held until satisfied. When all information is received, we have 28 days to complete our initial assessments but will do this as quick as we can for you.
We will complete a network evaluation to review the impact of your proposals on the existing network. At this stage, we will be able to advise if the diversion works can be completed by your appointed contractor (self-lay) or will need to be delivered directly by Severn Trent.
Application Requirements
Sewer Diversions must be designed to ensure that Severn Trent are provided with an equivalent sewer system with no loss of performance. We require that the sewer system is designed in line with the principles in Part B (Foul Water) and Part C (Surface Water) of the Design & Construction Guidance (DCG) for sewer Adoption. This document can be located here.
Sewer Diversions should be laid as a consistent gradient throughout and where the public sewer is increasing by 15% or greater, the sewer may need to be upsized to take into account a loss of hydraulic capacity.
Proof of ownership or occupancy for the land or property in question. (An official copy of register of title together with the title plan). This will allow us to confirm the diversion is within land that you control.
- The proposed route of the diverted sewer(s) coloured pink
- The abandoned sewer(s) coloured red
- The total length of sewer(s) being abandoned
- The site boundary coloured green
- A unique reference number for each manhole
- North Arrow
- Key for the design
- Note confirming the distance of the sewer in proximity to the building and the foundation
- Lateral connections into the diverted sewer (if any) coloured black
- An outline of any new and existing structures
- Existing and proposed ground levels
- Chainage/length (including at manholes)
- Manhole cover and invert levels
- Pipe sizes
- Pipe material
- Pipe bedding classifications
- Pipe gradient
- Pipe crossings (if any)
Note : Please ensure the manhole references & pipe numbers are consistent with the drainage layout plan.
Phase 1 Habitat Survey Report or a statement from Environment Engineer stating that no protected/endangered flora/fauna will be affected. This will allow us to understand any potential environmental impact.
Note: If the sewer diversion is taking place within a domestic garden, then the following statement (in a form of a formal letter, dated and signed by the applicant) would be acceptable: ‘I’m not aware of any specific ecological risks associated with in the development site and where the sewer diversion works will take place. The works will take place in a domestic garden and there are no known protected species within the area’.
CCTV Survey Report should be a full Survey Report in PDF format; videos are not required at this stage. The CCTV survey should be of the entire length you wish to divert and will allow us to confirm and identify any existing connections and ensure no customer could be accidentally disconnected due to the diversion.
A copy of the Planning Permission for the site. (If Planning at this point has been obtained). This will allow us to confirm the necessity of the diversion.
Ensure all required documents are provided to prevent delays to your application
If you require any help with the application, please contact our Developer Services team on 0800 707 6600 or at New.Connections@severntrent.co.uk
- First, you must complete an application through either our Online form or our PDF form provided below. The form should be submitted with all the information requested below and an initial application fee which will also be required.
We will complete a network assessment to determine the viability of the proposed diversion and to make a determination on if the diversion can be delivered Self-Lay or direct by Severn Trent.
Severn Trent Lay Diversion
If it’s determined that a diversion needs to be delivered directly by Severn Trent, our Network Solutions team will contact you directly outlining the next steps involved with delivering the diversion.
Self-Lay Diversion
After network evaluation, Self-Lay diversions will then undergo technical assessment. At this stage we will provide you with a direct single point of contact who will work with you to ensure your designs are compliant with our required standards. If we require any design changes, we will place your application on hold until you resubmit to us.
Fees
Our fees are detailed in our latest charging booklet
The fees are percentages calculated based on our estimated construction cost and are split into three elements.
Cash Bond – This is 20% of our estimated construction costs for the works, a minimum of £5,000.00. This money is held as an insurance against damage to the public sewer to ensure other customers continuity of service. This money will be returned to you once step three has been completed and is held in case we need to fix or complete any work on the diversion.
Inspection Fee – This is 6% of our estimated construction costs, a minimum of £500.00. This is to cover the Construction Project Manager (Severn Trent Inspectors) costs who will be present at various points during the diversion.
Administration Fee – This is a set fee of £214.77. This is to cover the required work to draft and complete the agreement
Agreement
We will issue the agreement to you within 14 days of receiving the payments quoted in the technical compliance and on receipt of the RFI. The agreement must be signed by all parties before any work on the diversion starts.
Once the agreement has been signed, you will be able to make an appointment with your appointed Construction Project Manager (CPM) who will complete a pre-start meeting with you. They will go over the inspection process, your construction plan and proposed materials. Your CPM will provide their direct contact details and will be available to support you during construction.
On request, we will allow a pre-start meeting to be arranged prior to the agreement being signed by all parties, but the agreement must be in place before construction begins.
Once the agreement has been signed and the pre-start completed, construction can start. Your Construction Project Manager (CPM) will discuss the inspection regime during the pre-start but will usually constitute both scheduled inspections booked by your contractor and unscheduled inspections where we will arrive on-site unannounced to check the works. The number of inspections will depend on the length and complexity of the diversion.
Whatever the inspection regime, you must always schedule an inspection for when you wish to turn the sewer flows into your diverted sewer.
When construction of the diversion has been completed the following information will need to be provided:
- S185 As-built drawing.
- Completed as built data collection form (template provided by Severn Trent).
- Satisfactory CCTV survey that shows the new sewer with no defects.
- A copy of the relevant sections of your H&S file at this stage showing site specific risks encountered (this may be provided at any time prior to final sign off)
- Inspection sign off by the CPM.
Once all the above has been provided & accepted we will issue a letter to you confirming the completion of the works and placing the diversion on a 12-month liability period.
During the 12-month liability period, we will monitor the sewer to ensure no defects or issues occur. Any defects or issues as a result of the diversion may result in further works needing to be completed by yourself.
When we issue this letter, will also return your cash bond back to you.
- Around 2 months before the liability ends a final inspection will be booked by your CPM to check the diverted sewers are still satisfactory. If any remedials are identified these will need to be completed by yourself.
When the sewers are signed off, we will then issue a liability end letter which is your confirmation the sewers are now fully our responsibility and you have fulfilled all the terms of the agreement.
What we do
If your building works or highway construction comes close or directly affects our mains, we offer a budget or full cost application to assess the impact on our clean water assets to price and design a diversion if required.
Application type
We offer two types of application, budget and full cost. However, in some instances your scheme may be deemed as complex, in this scenario one of our team will be in contact to discuss next steps and costs.
What we need
- Application fees : £758.22
- Completed application form.
- Site overview plan.
- Proposed construction drawings for works.
At this stage if any additional plans are available (i.e change in levels, depths of construction) this will make our assessments and our quotation more accurate.
What we need
- Application fees : £1,781.92
- Completed application form.
- Site overview plan.
- Proposed construction drawings for works.
- CAD drawing in .dwg format for the design overlay.
- Details of changes in levels.
- Details of any depths of construction.
At this stage if trial holes, GPR or CBR are available, this will help with the accuracy and quotation of our assessments.
You can apply online here :
What happens next
Once you have submitted your application, we will send you an acknowledgement letter and notify you if there are any payment or plans outstanding. Once we have received all the information, we endeavour to return all applications within 42 days.
In some instances for example major highways or geotechnical conditions, we may classify your scheme as complex. In these rare situations one of our project engineers will be in touch to discuss your application.
When completing this assessment we consider both the impact of the construction and the final position of the assets once work is completed. Following review we will issue you with a copy of our assessment, highlighting any assets that are impacted. In some instances there may be an opportunity to further reduce the scope by providing site investigation or additional plans.
Depending on the application that you selected, we will issue either a budget estimate and water record or a detailed design drawing and full cost quote. Once you have a chance to review these documents we will happily discuss the scope of the works or any queries related to the works. All our quotes carry a validity period of 6 months, in which they will need to be accepted.
In the instance you have selected a budget quotation you can upgrade this to full cost for £1,023.70
If you are satisfied with your quote and design, please return signed offer letter and make the required payment.
A pre-start meeting will be scheduled between the project engineer and one of our construction delivery partners. During this meeting, we will discuss the project timeline, health and safety considerations (CDM), and the specific requirements for your works. Our goal is to complete all works within 90 days. However, in certain cases - such as large-scale projects, road closures, or specific program requirements - the timeline may extend. In such instances, we will collaboratively agree upon a mutually suitable delivery date.
A final account will be produced, following completion of the project, this will include all project costs incurred.
Disconnections
If you require a disconnection at your property, here’s some information for you to find out more.
What is a permanent disconnection?
Your site may require a permanent disconnection. This is free - all we have to do is disconnect on the public boundary. So if you ever need the supply again, you’ll need to pay to replace the pipework, plus our normal new connection charges.
Things to bear in mind
If your water supply also serves another customer’s property, then we might have to separate the existing supply first, and you would need to pay for this. In these cases, we normally do a site survey to estimate the amount of work and the costs.
If the property is still occupied, we can’t disconnect the water supply. If this is the case, please let us know when the property will be empty.
The registered owner must authorise a permanent disconnection. If the form filler isn't the owner but seeks disconnection, please include written authorisation from the owner.
Surface water drainage charges may still apply for commercial properties after water supply disconnection. This is approved by Ofwat, as the property benefits from our rainwater removal services.
You can also call us on 03457 500 500 if you have any questions about disconnections.