Water supplies for firefighting and the evidence required
Fire authorities want hydrants in the right places and proof of the flow behind them. The requests take weeks, so they belong at feasibility rather than at pre-commencement.
Firefighting water supplies evidence is the item most often missing from an otherwise complete major application, and it is the one that stalls discharge of conditions months later. What the fire and rescue authority wants is simple enough to describe: hydrants in the right places, a demonstrated flow and pressure at those hydrants from the water undertaker, and a clear position on any suppression system demand. What makes it slow is that none of that information comes from the design team. It comes from two external organisations, each with its own request process and its own queue.
Start the requests at the same time you commission the topographical survey. Not when the highways comments arrive.
What the fire authority actually asks for
The statutory background sits in the Fire and Rescue Services Act 2004. Section 38 places a duty on the fire and rescue authority to take steps to secure an adequate supply of water for firefighting, and section 39 lets it require the water undertaker to fix fire hydrants. The Water Industry Act 1991 carries the corresponding duties on the undertaker, including provision of hydrants on request and the supply of water for firefighting without charge.
Against that background, a consultation response on a housing or commercial scheme typically asks for four things:
- A hydrant layout drawing showing existing hydrants within reach of the site and any new hydrants proposed.
- Confirmation from the water undertaker of the flow and pressure available at the relevant points on the network.
- Access arrangements for appliances, with turning, standing and reach dimensions.
- Where a suppression system is proposed, its demand and how it will be met.
None of that is onerous once the information exists. Obtaining it is the work.
Hydrant provision and spacing
Approved Document B sets the building regulations position on access and facilities for the fire service, including how far a hydrant should be from an entry point and how far apart hydrants should be on a development. The figures differ between the volume covering dwellings and the volume covering other buildings, and they interact with whether the building has fire mains. Read the edition in force rather than a remembered number, because this part of the document has been amended.
Where existing hydrants are too far away, new ones are provided at the developer's cost, usually secured by a condition or by a section 106 obligation. The hydrants themselves are installed on the undertaker's main, so the timetable belongs to the undertaker rather than to your groundworks contractor.
A drawing that helps the officer shows the existing hydrants with their reference numbers, the proposed hydrants, the distances to building entry points, and the appliance route. Put it on the same base as the site layout so the two can be read together.
Flow and pressure evidence from the undertaker
Ask the water undertaker for a flow and pressure test, or for modelled network data, at the points where hydrants will serve the development. Undertakers offer this as a chargeable service, usually alongside the water supply and sewer capacity enquiries, and lead times of several weeks are normal.
Two cautions. Modelled data is not the same as a live test, and a fire authority may accept one and not the other depending on the scheme. And a result taken at a summer peak hour is not the same as one taken at three in the morning, so record the conditions of the test with the result.
Where the recorded flow falls short of what the fire authority requires for the category of risk, you are into reinforcement: an uprated main, a new connection or a larger diameter run back to a stronger part of the network. That is a cost and a programme item, and it is far better identified at feasibility than at pre-commencement. The wider capacity picture belongs in a Utilities Assessment covering water, foul drainage, power and communications together.
Where flows fall short: tanks, pumps and alternatives
Static supplies are a recognised answer where the network cannot deliver. A dedicated tank of stated capacity, an open water source with a hard standing and a draw-off point, or a pumped arrangement can all satisfy a fire authority, provided the capacity, the access and the maintenance regime are agreed.
The planning consequences are real. A tank takes space, needs vehicular access for an appliance and may need screening. A pond used as an open water supply cannot also be the attenuation feature at variable level unless the draw-off works at the lowest operating level. Raise these early with the drainage engineer rather than discovering the clash at technical design.
Maintenance is the part that gets forgotten. Whoever manages the estate has to keep the access clear and the supply functional for the life of the development, and that obligation belongs in the management company documents, not in a condition that nobody reads again.
Suppression system demand
Where sprinklers or another suppression system are proposed, the water demand is set by the relevant standard for the system type, with residential and domestic systems and commercial systems designed to different standards and different durations.
The two numbers that matter to the network are the design flow rate and the duration it must be sustained. Where the mains cannot provide both, the design uses a tank and pump set sized to the standard, and the tank then becomes a building and a planning matter in its own right.
On residential buildings above the height threshold, suppression is not optional and the fire strategy drives the layout rather than following it. A Fire Safety Strategy to the relevant British Standard is a fire-engineering document: a licensed or competent professional is legally required to prepare work of this kind, and any AI-assisted draft is a starting point for that professional rather than a substitute.
Where this lands in the planning submission
For relevant buildings, the fire statement route under article 9A of the Development Management Procedure Order 2015 brings the Health and Safety Executive in as a statutory consultee at Planning Gateway One. Water supplies for firefighting is one of the matters the statement addresses, alongside site layout and appliance access.
A Fire Statement at Gateway One must be prepared by someone with the necessary fire-engineering competence under the Building Safety Act 2022 framework, and it is a document where professional authorship is legally required rather than merely advisable.
For schemes below the threshold, the material still needs a home. Put the hydrant drawing and the undertaker's correspondence into the application as supporting documents, and summarise the position in a short section of the covering statement. Schemes adding storeys to existing blocks raise the same questions about rising mains and appliance access, and the evidence expected is set out in our note on airspace development above flats.
Presenting the correspondence
Submit the material as received rather than as summarised. Fire officers and building control bodies read the original.
A complete pack contains the undertaker's written response with the test or model reference and the date, the hydrant layout drawing at a readable scale, the fire and rescue authority's consultation response if one has already been obtained through pre-application, and a short note reconciling the requirement with the available supply. Where a shortfall exists, say so and state the proposed remedy rather than leaving the reader to work it out.
Illustrative example: a 62-dwelling scheme on a village edge, served by a 100mm main at the end of a long run. The modelled flow was adequate for domestic demand and short of the fire authority's requirement. The resolution was two new hydrants plus a short length of upsized main back to the junction, agreed with the undertaker at feasibility and secured by condition. Found at pre-commencement instead, it would have delayed the start by a full season.
This is general guidance, not legal advice; check the position with your local planning authority, the fire and rescue authority or a qualified professional before relying on it. For specialist technical reports, qualified professional input may be required. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Enter your postcode on PlanScope to see which fire and infrastructure reports your scheme is likely to need.
Frequently asked questions
Who is responsible for providing fire hydrants on a new development?
The fire and rescue authority identifies the requirement under the Fire and Rescue Services Act 2004 and can require the water undertaker to fix hydrants. The undertaker installs them on its main. The developer normally pays, with the obligation secured by planning condition or a section 106 agreement, and the installation timetable belongs to the undertaker.
How do I get flow and pressure data for a site?
Ask the water undertaker for a flow and pressure test or modelled network data at the points the hydrants will serve. It is a chargeable service, usually requested alongside water supply and sewer capacity enquiries, with lead times of several weeks. Record the date and conditions of the test, because results vary through the day and the year.
What happens if the mains flow is below what the fire authority requires?
You are into network reinforcement or a static supply. Reinforcement means an uprated or larger main back to a stronger part of the network. A static supply means a tank of agreed capacity, or an open water source with hard standing and a draw-off point. Both carry cost, space and maintenance consequences worth identifying at feasibility.
Does a fire statement cover water supplies?
Yes. For relevant buildings, the fire statement required under article 9A of the Development Management Procedure Order 2015 addresses water supplies for firefighting alongside site layout and appliance access, with the Health and Safety Executive consulted at Planning Gateway One. It must be prepared by someone with the necessary fire-engineering competence.
Can a drainage attenuation pond double as a firefighting water supply?
Sometimes, but only if the draw-off point works at the lowest operating water level and an appliance can reach hard standing beside it. A pond designed to empty between storms will not satisfy a fire authority. Raise the question with the drainage engineer at concept stage rather than at technical design.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.