What is a Section 106 sewer connection? The right to connect, explained

A section 106 sewer connection is the statutory right, under section 106 of the Water Industry Act 1991, for the owner or occupier of a property to connect its drains to the public sewer. It is a right, not a favour. A sewerage undertaker cannot refuse it simply because the network is busy, and that single principle moves thousands of new homes and commercial buildings onto the public sewer each year. It is also, constantly, confused with the unrelated planning obligation that shares the same number.

Confirming the foul route early is often what separates a smooth start on site from a stalled one, which is why we tackle it head-on when we prepare a foul drainage strategy for planning. This guide explains what the drainage section 106 covers, what you can and cannot connect, the narrow grounds on which a water company may say no, and how the right now sits alongside sewer adoption, building control and the surface water rules bearing down on it.

The right to connect is one of the oldest and strongest entitlements in English water law. In 2026 it is also one of the most contested.

What is a Section 106 sewer connection?

A section 106 sewer connection is the legal right of an owner or occupier to make their drain or private sewer communicate with the public sewer, so that foul or surface water can discharge into the public system. The right attaches to the property, not the person, and it passes with the land when the property is sold. It helps to follow the drainage chain from the building to the main.

• The private drain or sewer carries flow from the building to the boundary and is the property owner's responsibility.
• The lateral drain runs from the boundary to the public sewer and is usually the water company's responsibility once vested.
• The public sewer is the adopted main the connection ultimately reaches, maintained by the sewerage undertaker.

Section 106 governs the moment of connection between that private pipework and the public sewer. On its own it does not make the pipe adoptable, and it is separate from the distinction between foul, surface and combined sewers that decides which public sewer a given flow may even enter.

What is the difference between a Section 106 drainage and a planning Section 106?

They are two different laws that happen to share a label. The drainage section 106 is a water-industry right to connect to the public sewer, under the Water Industry Act 1991. The planning section 106 is a negotiated agreement between a developer and a council, under section 106 of the Town and Country Planning Act 1990, that secures obligations tied to a planning permission. Different Acts, different bodies, different jobs, and developers conflate them constantly.

If someone on a project says the section 106 is "sorted", it is worth asking which one they mean. A signed planning agreement tells you nothing about whether the sewerage undertaker has accepted the connection, and the reverse is just as true.

What can you connect under Section 106, and what is excluded?

The right in section 106(1) is broad: an owner or occupier can discharge both foul water and surface water into the public sewer. But section 106(2) carves out real exclusions. You cannot use the right to push the wrong kind of flow into the wrong kind of sewer, or to discharge things the public system was never built to take. The statutory wording is the anchor for everything that follows.

The exclusions matter as much as the right, and they are set out plainly in the text of section 106 on legislation.gov.uk.

• Certain trade effluent cannot be discharged through the section 106 right to connect.
• Unlawful discharges are excluded — anything the sewer is not permitted to receive.
• Wrong-class connections are barred: no foul water into a surface-water-only sewer, and no surface water into a foul-only sewer.
• Storm-water overflow sewers cannot take a direct drain or sewer connection.

Where a scheme mixes flows or sits near the wrong class of sewer, confirming which public sewer is lawfully available belongs in the surface water drainage strategy or the foul strategy, not at connection stage.

Can a water company refuse a Section 106 connection?

Yes, but only on narrow grounds and only inside a tight window. Under section 106(4) a sewerage undertaker may refuse where the manner of construction or the condition of the drain or sewer falls short of its standards, or where the connection would be prejudicial to its sewerage system. It must serve any refusal within 21 days of the connection notice.

A water company has 21 days from the connection notice to object, and only on construction, condition or system-prejudice grounds. A network short of capacity is not one of them.

Silence is not neutral. If no valid refusal is served inside the 21 days, the connection may proceed. The permitted grounds are limited to two.

• Construction or condition: the drain or sewer is not built or maintained to a standard the undertaker can reasonably accept.
• Prejudice to the system: the specific connection, as proposed, would harm how the sewerage network operates.

Lack of headroom in the network is not, by itself, a lawful reason to refuse, redirect or delay a connection. Where a water company raises capacity as the obstacle, it is worth understanding how water companies engage with the planning process before accepting the position.

Does a lack of sewer capacity allow refusal? Barratt Homes v Welsh Water

No. That question was settled at the highest level in Barratt Homes Ltd v Dŵr Cymru Cyfyngedig (Welsh Water) [2009] UKSC 13. Welsh Water had tried to make a developer connect at a more distant point of the undertaker's choosing, to protect its network, rather than at the nearer point the developer had selected. The Supreme Court disagreed, by a majority of four to one.

The court held that the developer, not the undertaker, chooses the point of connection, and that inadequate capacity in the existing sewer cannot be used to refuse or reroute a connection made under section 106. The undertaker's remedy for a network that cannot cope is to improve the network, not to turn away a lawful connection. The full Supreme Court judgment and case record set out the reasoning.

In Barratt Homes v Welsh Water the Supreme Court confirmed, by 4–1, that the developer chooses the connection point and that a lack of sewer capacity cannot justify refusing a Section 106 connection.

The ruling has governed the right to connect ever since. It is why "the sewer is full" has never been a complete answer to a section 106 notice.

Is connecting the same as adopting a sewer?

No. Connecting a drain under section 106 lets the flow in; it does not hand the pipe to the water company. Adoption is the separate step that transfers a sewer into public ownership and maintenance, either by a section 104 agreement settled before construction or, less often, by a section 102 adoption of an existing sewer. Connecting is about the flow being allowed in; adopting is about who owns and maintains the pipe afterwards.

Most developments need both, and in the right order. Our guide to Section 104 and Section 102 sewer adoption agreements covers the adoption side in full; this page stays with the right to connect.

How do you apply for a Section 106 connection?

You serve the sewerage undertaker a formal section 106 connection notice, then let the statutory clock and the infrastructure paperwork run their course. It rewards starting early, because a capacity enquiry and the connection charge sit on their own timetables. In practice the sequence runs like this.

1. Confirm the point of connection. Identify the public sewer, its type (foul, surface or combined) and a realistic connection point. A mains connection is generally expected where a public sewer lies within about 30 metres per property served.
2. Serve the Section 106 connection notice. Give the sewerage undertaker formal notice of the proposed connection, with the detail it needs to assess construction, condition and system effect.
3. Allow the 21-day period. The undertaker has 21 days to refuse on valid grounds. If no valid refusal is served, the connection can proceed.
4. Pay the infrastructure charge. A standard infrastructure charge is normally payable per connection; it reflects the load a new property adds to the wider network.
5. Connect under supervision. Make the physical connection to the undertaker's requirements, which may mean it carries out or supervises the work, and obtain a street works licence if the connection is made in the highway.

Is the right to connect changing in 2026?

It is under more pressure than at any point since Barratt. Two forces are squeezing the right to connect surface water in particular: a discharge hierarchy that now treats the sewer as a last resort, and a formal government review of the near-automatic entitlement itself. Foul connections are less exposed, but the direction of travel is unmistakable.

The 2025 National Standards for Sustainable Drainage Systems put the public sewer at the bottom of the surface water discharge hierarchy: reuse first, then infiltration, then a watercourse, and only then the sewer. A planning drainage strategy now has to justify why surface water is reaching the sewer at all, rather than treating the sewer as the default. Our explainer on the 2025 National Standards and where they stand in 2026 sets out the detail.

Under the 2025 National Standards the surface water discharge hierarchy runs reuse, infiltration, watercourse, then a surface-water sewer, with a combined sewer as the last resort. Cost alone never justifies skipping a tier.

The entitlement itself is now being reviewed. The Independent Water Commission, led by Sir Jon Cunliffe, flagged new development adding unplanned load to the network. The Government's January 2026 water white paper, A new vision for water, then confirmed that ministers, working with the housing department, are reviewing the right to connect to both water supply and the sewerage system. As the House of Commons Library briefing summarises it, the current near-automatic right "may become diluted and subject to capacity being available".

Wales has already gone further. Since Schedule 3 of the Flood and Water Management Act 2010 was commenced there, the right to connect surface water is conditional on a sustainable drainage system being approved. England has not commenced Schedule 3, so for now the Barratt Homes position still holds, but it is no longer safe to assume it always will. For any scheme leaning on a sewer connection for surface water, building the hierarchy into the drainage strategy from the outset is now programme risk as much as compliance.

Three separate regimes: planning, connection and building control

A recurring cause of delay is treating planning permission as if it also authorises the sewer connection. It does not. Three separate consents govern getting drainage built and connected, and clearing one does not clear the others.

• Planning permission decides whether the development, including its drainage strategy, is acceptable in land-use terms.
• The Section 106 connection is the water-industry right to physically connect to the public sewer.
• Building control (Approved Document H) governs the technical standard of the drainage installation itself, and neither regime checks the other.

Connecting to a public sewer without authorisation is an offence under the Water Industry Act 1991, so the connection regime cannot be skipped even where planning and building control are both satisfied. Off-mains, a different regime again applies through the General Binding Rules for small sewage discharges. Keeping the three consents distinct, and confirming the discharge point before it becomes critical, is most of what stops drainage holding up a start on site.

Frequently asked questions