Budgeting a set of utilities capacity enquiries

Utilities capacity enquiries sit entirely outside the planning fee, and on a small site they are routinely the cost nobody budgeted. Each network has its own enquiry process, its own charging statement and its own programme, and none of them is bound by your determination date. Budget for five separate conversations: electricity, water supply, foul and surface water, gas, and telecoms, plus legal fees for any easement or adoption agreement that follows.

The figures are published, which is the useful part. Every distribution network operator and water undertaker publishes a charging statement setting out what it charges for enquiries, designs and connections, so you can cost this properly rather than guessing. The figures are revised, usually annually, so work from the current statement.

Which enquiries to raise, and in what order

Raise them in the order in which the answers change your layout.

1. Electricity capacity, because a substation needs a plot with permanent access and that plot has to come out of your developable area.
2. Foul drainage capacity and the point of connection, because a pumping station or an off-site sewer requisition is the next biggest layout item.
3. Surface water, because the discharge point and any attenuation volume shapes the open space.
4. Water supply, which is usually the most straightforward but can require a main extension.
5. Gas, if you are using it at all, and telecoms, which rarely change the layout but have their own lead times.

For a single self-build plot you may be able to run all five in parallel. On anything above a handful of units, sequence them, because the electricity answer often changes the drainage layout and redoing an enquiry costs another fee and another wait.

Keep a simple register: enquiry reference, date raised, fee paid, promised response date, actual response, validity expiry. That register is what you will hand to a funder, and it is the thing most self-builders wish they had started on day one.

Electricity: a budget estimate, then a formal offer

Electricity connections work in two stages and the words matter.

A pre-application or budget estimate gives an indicative cost and tells you whether the local network has capacity. It is quick, often low cost or free for small connections, and it is not binding. Use it to test feasibility and to find out early whether reinforcement is needed.

A formal connection offer is a quotation you can accept. It sets out the connection charge, the works the network operator will carry out, the works you may procure yourself, any reinforcement contribution and the conditions attached. Distribution network operators work to published standards of performance for issuing quotations, so ask what the stated timescale is for your type of connection when you raise the enquiry, and diarise it.

Two things to settle at the offer stage. Whether the works are contestable, meaning an independent connection provider could carry them out more quickly or at lower cost, with the non-contestable elements remaining with the network operator. And where the substation or the metering position physically goes, because the operator will want unrestricted vehicular access to it at all hours and a legal easement, and a substation tucked behind a gate is not acceptable to them.

Budget lines for electricity: the enquiry or design fee, the connection charge, any reinforcement contribution, your own design fees if you appoint a provider, legal costs for the easement, and the cost of the land the substation occupies.

Water supply and foul capacity

The water undertaker deals with supply and, in most areas, with sewerage, and the enquiry processes are separate even where the company is the same.

A pre-development enquiry asks the undertaker whether there is capacity in the water main and in the foul and surface water networks, and where it will accept a connection. The answer can come back with conditions: a restricted discharge rate, a requirement to connect at a different manhole, or a phasing restriction tied to the undertaker's own improvement programme.

The statutory framework is worth knowing because it tells you what you can insist on. Section 106 of the Water Industry Act 1991 gives a right to connect to a public sewer, subject to conditions. Section 98 allows a sewer requisition where new public sewerage is needed, and section 41 does the equivalent for a water main. Section 104 is the adoption agreement route for sewers built as part of the development, which usually comes with a bond.

Infrastructure charges are published in the undertaker's charging arrangements and are set per connection, so they scale with unit numbers and are simple to budget once you know the scheme. What is harder to budget is off-site work, which only becomes clear once the capacity assessment comes back. On a brownfield plot the answer also interacts with ground conditions, so run the capacity enquiry alongside the work covered in budgeting ground investigation for a brownfield plot rather than after it.

Where the planning application needs the position evidenced, a Foul Sewage Assessment sets out the proposed means of disposal, the capacity position and the undertaker's response, and a Utilities Assessment covers the wider picture across all the networks.

Gas and telecoms, and their lead times

Gas connections follow a similar quotation process through the gas transporter or an independent gas transporter. On many new schemes gas is no longer being installed at all, given the direction of building regulations on heating, so decide that before you pay for an enquiry you will not use.

Telecoms is the one people leave to the end and then discover is on the critical path for occupation rather than for construction. New dwellings in England have to be built with gigabit-ready in-building physical infrastructure and, where it can be obtained within the cost cap, a gigabit-capable connection, under the building regulations requirement in Approved Document R. That means a duct route, a termination point and evidence that a connection was sought. The provider's own build programme for a new estate road can run to months.

Raise the telecoms enquiry when you raise the electricity one. It costs very little and the evidence you get back is what demonstrates compliance.

Validity periods, and why quotations expire

Every connection offer has a validity period stated on its face, and once it lapses you are re-quoting at current prices against current network capacity. On a scheme where planning takes nine months and the land deal takes another three, a quotation obtained at the start of the process is usually dead by the time you want to accept it.

Two practical responses. Get budget estimates early, for the appraisal, and formal offers late, when you are close to accepting. And where a formal offer has to be obtained early, perhaps because a funder wants certainty, note the expiry date in the programme and ask the operator what happens on re-quotation if network capacity has been allocated elsewhere in the meantime. Capacity is often allocated on a first-accepted basis, and a neighbouring scheme accepting its offer before you accept yours can change your answer entirely.

That risk is the strongest argument for paying the acceptance fee earlier than feels comfortable on a constrained network.

Diversions and build-over agreements

Diversions are the item that turns a viable plot into a marginal one.

Section 185 of the Water Industry Act 1991 provides the route for requiring a water main or public sewer to be moved, at the developer's cost. Electricity and gas diversions follow their own processes. In all cases expect a design fee, a long programme, a requirement to provide an easement over the new route, and a cost that is hard to estimate until the design is done.

Where the asset can stay put, a build-over or build-near agreement with the undertaker is usually quicker and considerably less expensive than a diversion, subject to its technical conditions on foundation design, access to manholes and protective measures. Settle which route you are taking before the foundation design is fixed.

Budget for the legal cost on both sides. Easements, adoption agreements and build-over agreements all involve the undertaker's solicitors at your expense.

Why this belongs before the layout is fixed

Three items from the list above take land: the substation plot, a pumping station, and the easement over any diverted or retained main. A layout drawn before those answers are back will change, and a layout that changes after planning permission means a section 73 application or a fresh one.

The second reason is commercial. Connection and infrastructure charges, reinforcement contributions, diversions and adoption bonds together can run to a material proportion of the infrastructure budget on a small site, and none of it appears in a planning fee calculation or in a typical agent's fee quotation. What is and is not included in professional fees is set out in what a planning agent's fixed fee usually includes, and utilities almost never are.

So do the enquiries early, keep the register, diarise the expiry dates, and treat the published charging statements as the source rather than a figure someone quoted on a previous site.

If you are costing the planning documents alongside the utilities work, PlanScope pricing sets out the one free report, the £50 per report option and the Professional tier at £150 per month or £600 per year. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

This is general guidance, not legal advice. Charges and timescales are set by each network operator and undertaker and are revised regularly, so check the current charging statement before relying on any figure.