Sewer connection and infrastructure charges explained

Connecting a new house to the public sewer costs more than the connection. There is the connection itself, an infrastructure charge levied per new property, possibly a build over agreement, possibly a requisition where no sewer is within reach, and inspection and adoption charges if you are building a length of sewer that will be handed over. None of it is covered by the planning fee or the levy, and the undertaker's timescales do not run in parallel with the council's.

The right to connect and how it is exercised

Section 106 of the Water Industry Act 1991 gives the owner or occupier of premises a right to connect drains and private sewers to the public sewer. It is a statutory right, not a favour, which matters when a conversation with the undertaker starts badly.

The right is exercised by giving notice. The undertaker has a limited period in which to refuse, and it may only do so on specified grounds, broadly that the mode of construction or condition of the drain is not satisfactory, or that the connection would be prejudicial to the sewerage system. A refusal can be appealed, and in practice most disputes are resolved by changing the connection detail rather than by arguing about the ground.

Two practical points sit behind the statute. Surface water is not accepted into a foul sewer as a matter of course, and on most new development it will be refused outright. And the right to connect does not oblige the undertaker to make capacity available, which is the issue that stops schemes rather than the connection itself. On a single plot in an established street that rarely bites. On twenty houses at the end of a village it frequently does.

Connection charges against infrastructure charges

These are different things and they appear on the same invoice, which causes confusion.

The connection charge covers the physical work: the new connection to the sewer, the excavation, the traffic management if the sewer is under the carriageway, and the inspection. Where the undertaker carries out the work, the price reflects depth, material and location. Where a contractor does it under supervision, the charge is smaller but the inspection still applies.

The infrastructure charge is different in kind. It is a per-property charge levied under the Water Industry Act towards the cost of reinforcing the wider network, and each undertaker publishes it in charging arrangements that are revised annually. There are usually separate water and wastewater elements, and there are offsetting arrangements in some circumstances.

Because the figures change every year, take them from the undertaker's current published charging arrangements rather than from an older appraisal. Ask specifically whether the quote includes the infrastructure charge or only the connection. On a single dwelling the two together are a modest line in the budget. On a scheme of thirty homes the infrastructure charge alone is worth modelling properly, because it is levied per property and falls due as the plots connect.

Build over and build near agreements

Building over or close to a public sewer needs the undertaker's agreement, and this is separate from Building Regulations approval even though the two are often confused.

The trigger is usually a sewer within a stated distance of the proposed structure, commonly three metres, but the undertaker's published policy governs. The application asks for drawings showing the sewer position, the foundation design and the protection proposed, and it attracts a fee.

Find the sewer before you design the foundations, not after the piling rig arrives. Sewer records are available on request and are not always accurate, so on a tight site a survey to confirm the line and depth is money well spent. A sewer discovered during excavation turns into a redesign, a diversion at the developer's cost, or both.

Where diversion is unavoidable, treat it as a separate project with its own design approval, price and programme, in the same way as the other utility connection costs in a development budget.

Pre-development enquiry and capacity

Every undertaker offers a developer enquiry service that will confirm the position of assets, the point of connection and whether capacity exists. Use it before you exchange on the land.

Where capacity is short, the options are a contribution towards off-site reinforcement, a phasing arrangement so occupation follows the upgrade, or a requisition. Sections 98 to 101 of the 1991 Act allow a developer to requisition a public sewer where one is not available, with the developer funding the works subject to an income offset over a period of years.

Requisition timescales are long, and they are outside your control. Design, legal agreement, wayleaves across third-party land and construction can run to a year or more, and the council will often impose a negatively worded condition preventing occupation until foul drainage is available. That condition is reasonable, and it puts the undertaker's programme directly on your critical path.

Pumping stations, adoption and inspection

Where levels do not allow a gravity connection, a pumping station is the usual answer and it changes the cost profile considerably.

A station built to the undertaker's design and construction standards can be offered for adoption under section 104, which transfers long-term maintenance away from a management company. Adoption brings its own requirements: land ownership transfer, access, a commuted sum in some cases, and inspection at defined stages.

The alternative is a privately maintained station, which is less costly to build and creates a permanent service charge liability that conveyancers will raise on every sale. On a scheme of more than a handful of units, adoption is usually worth the extra design discipline.

Budget the inspection and adoption charges as a line of their own, and allow for the technical audit that precedes the final certificate. Allow programme time too, because the audit happens when the station is built and commissioned rather than when the drawings are approved.

Sequencing with the planning condition

The drainage condition on a planning permission and the undertaker's process are separate tracks that have to be run together.

1. Make the pre-development enquiry before the planning application, so the strategy reflects what is actually available.
2. Submit the foul drainage evidence with the application rather than leaving it to a condition, where the scheme is anything more than a single dwelling.
3. Apply for the build over agreement as soon as the foundation design is fixed.
4. Serve the section 106 connection notice with enough lead time for the undertaker's period to run.
5. Where a requisition or reinforcement is needed, start the legal agreement before the planning decision, because that work does not depend on the permission.

A Foul Sewage Assessment is what the council will expect where the connection is not straightforward, and it should set out the point of connection, the capacity position and the evidence from the undertaker. Surface water goes in the Drainage Strategy rather than being folded into the same document, because the two are assessed by different consultees.

See PlanScope pricing if you want those documents drafted while the undertaker's enquiry is running.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.