Sewer connections
Sewer connections and adoptions, prepared and submitted for you
Section 106 connections, Section 104 adoption, build-over agreements, requisitions and diversions in England and Wales, plus Scottish Water applications. We work out which applications your site needs, prepare them with the drawings the water company expects, and keep them moving alongside the build.
Most sites need more than one sewer application
New drainage usually needs the water company's approval in more than one way. Connecting a drain or private sewer to the public sewer needs a Section 106 application. New sewers that will serve more than one property are usually offered for adoption under Section 104. Building over or close to an existing public sewer needs consent, often through a build-over agreement.
Each has its own form, fee, drawings and inspections, and each water company runs them slightly differently. Missing one is a common cause of late surprises: a Building Control query about a sewer under the footprint, or a connection date that can't be booked because the paperwork isn't approved.
We check your drainage layout against the public sewer records, tell you which applications you need and prepare them with your drainage designer. Then we deal with the water company until each one is approved.
We handle sewer applications for
- Section 106 connections to public sewers
- Section 104 adoption agreements
- Section 98 sewer requisitions
- Section 185 sewer diversions
- Build-over and build-near agreements
- Pre-development capacity enquiries
- Foul and surface water, for single homes to large sites
Which sewer application do you need?
Each one comes from a different section of the Water Industry Act 1991, plus the Building Regulations for work near sewers.
Section 106: connect to a public sewer
Your legal right to connect a drain or sewer to a public sewer. You give notice to the water company, and it can refuse only on limited grounds. Needed for almost every new building on mains drainage.
Section 104: sewer adoption
An agreement for the water company to adopt new sewers once they are built and inspected. Usual on developments where sewers serve more than one home.
Section 98: sewer requisition
You require the water company to provide a public sewer to serve your site, for example where the nearest one is some distance away, and pay the requisition charge.
Section 185: sewer diversion
If a public sewer runs where you want to build, you can ask the water company to move it. You pay for the diversion.
Build-over agreement
Consent to build over or within 3 m of a public sewer. Building Regulations Part H4 applies too.
Pre-development enquiry
Not a legal requirement, but it shows early whether the sewer has capacity for your site. Some companies may object at planning if it doesn't.
Section 106 and Section 104: how they differ
They are often confused, and many developments need both.
| At a glance | Section 106 | Section 104 |
|---|---|---|
| What it does | Connects your drain or sewer to an existing public sewer | Brings the new sewers you build into public ownership |
| Typical use | Every new building on mains drainage, including single homes | Developments with sewers shared by more than one property |
| Design standard | The water company's connection and inspection requirements | Water UK's Design and Construction Guidance (England, since 1 April 2020) |
| Charges | Application, inspection and connection charges from the company's published Charging Arrangements | Site-specific work only. No network reinforcement, and no asset payments under Ofwat's April 2026 rules for English companies |
On many developments you need a Section 104 for the new sewers and a Section 106 for where they join the public sewer. Some companies deal with the connection within the Section 104 process, so we check how yours works. Read our Section 106 guide.
Building over or near a public sewer
Public sewers often run through gardens and private land, not just under roads. If you plan to build over or within 3 m of a public sewer, you need the water company's consent, usually through a build-over agreement. Thames Water also applies this within 1 m of a public lateral drain. Building Regulations Part H4 applies as well.
Get the water company's consent before you submit your full plans application. It avoids delays at Building Control.
The criteria differ by company. Anglian Water's standard criteria, for example, cover sewers of 150 mm diameter or less, less than 3 m deep, with no more than 6 m under the building. Outside a company's standard criteria, expect more questions, or a diversion under Section 185.
Requirements vary by company, but expect to provide
- A site plan showing the sewer and the new building
- Foundation details and sections near the sewer
- The sewer's depth, size and condition, often from a CCTV survey
- How manhole access will be kept clear
Check before you dig foundations
Finding a sewer once the foundations are open means delay and cost. We check the public sewer records against your layout at the start of the job.
How we handle your sewer applications
You deal with us. We deal with the water company, its technical reviewers and the paperwork.
Records check
We check public sewer records against your layout and confirm which applications you need.
Capacity
On developments, a pre-development enquiry shows capacity problems before planning, not after.
Applications
We prepare the Section 106, 104 and build-over applications with your drainage designer's drawings.
Technical review
We answer the company's design queries and track approvals, fees and any security it asks for.
Connection and adoption
We line up inspections and the connection date, and follow the adoption through.
Sewers for Adoption has been replaced
Since 1 April 2020, new sewers offered for adoption in England must follow Water UK's Sewerage Sector Guidance and its Design and Construction Guidance. These replaced Sewers for Adoption, which some older drawings and specifications still quote.
If your drainage was designed to Sewers for Adoption, ask your designer to check it against the current guidance before it is submitted. A design that doesn't follow it will come back with queries, and the clock starts again.
SuDS: England and Wales differ
In Wales, new developments have needed approval from the SuDS approving body since 7 January 2019, as well as the water company's approvals.
In England, the part of the Flood and Water Management Act that would set up SuDS approving bodies is still not in force, as far as we are aware. Surface water is dealt with through planning and the water company. This could change, so we check the position for each site.
English water companies must also offer environmental incentives for sustainable drainage. The amounts and conditions vary by company, so a good surface water design can be worth checking against your company's offer.
Information for sewer applications
Send what you have. We'll tell you what is missing and who on your team can provide it.
- Site address and a location plan
- Drainage layout for foul and surface water, with levels and pipe sizes
- Building positions relative to any public sewer
- Number of homes or units, and flows for commercial buildings
- Surface water strategy, including any SuDS
- Planning permission and any drainage conditions
- Sewer surveys or CCTV reports, if you have them
What affects the cost of a sewer connection
Each water company publishes its sewer application fees and charges every year. Expect application and inspection fees for Section 106 and Section 104, and sewerage infrastructure charges per connection, reduced if the site was connected in the last five years.
The biggest costs usually come from the work itself: the depth of the connection, digging in the road, traffic management and any diversion.
Our own fee for managing the applications is agreed and fixed before we start.
Read the connection costs guideSewer connection questions
What is a Section 106 sewer connection?
It is your legal right to connect a drain or sewer to a public sewer, under Section 106 of the Water Industry Act 1991. You give the water company notice, and it can refuse only on limited grounds.
Do I need a Section 106 application for a single house?
In most cases, yes, if the new home's drains connect to a public sewer. It applies to single homes as well as developments.
What is a Section 104 agreement?
An agreement for the water company to adopt new sewers once they are built and inspected. In England they must be designed and built to Water UK's Design and Construction Guidance.
What is the difference between Section 104 and Section 106?
Section 106 is about connecting to an existing public sewer. Section 104 is about the water company adopting new sewers you build. Many developments need both.
Do I need a build-over agreement?
Usually, if you build over or within 3 m of a public sewer. The criteria differ by company, and Building Regulations Part H4 also applies.
Can a public sewer be moved?
Yes. Under Section 185 you can ask the water company to divert a public sewer, at your cost. It takes time, so raise it early.
Can the water company refuse a Section 106 connection?
Only on the limited grounds set out in the Act, broadly where the way the drain is built, or its condition, would harm the public sewer. Capacity concerns are usually raised at planning stage instead.
Who makes the connection to the public sewer?
It depends on the company and where the sewer is. Some companies make the connection themselves, others let your contractor do it under their inspection. We confirm the arrangement before work starts.
Do I need SuDS approval?
In Wales, most new developments need approval from the SuDS approving body. In England that system is not in force, as far as we are aware, so surface water is dealt with through planning and the water company.
Need sewer applications for your site?
Send us the drainage layout and site details. We'll confirm which applications you need and send a clear quote for managing them.