Firefighting water supply on a rural site

A rural site with no hydrant within reach of the proposed dwellings has a firefighting water problem, and it is usually solved with a charged static tank or an approved open water source plus hardstanding for a pumping appliance. The fire and rescue service will say so in its consultation response. If the answer is not on the drawings before that response arrives, the scheme either picks up a pre-commencement condition or loses weeks while a tank position is found.

This is one of the few technical issues on a small rural scheme where the cost is modest and the programme damage is large.

Why rural sites fail on water supply

Mains in a rural lane are often small-diameter distribution pipes laid to serve a handful of properties. They carry enough for domestic demand and nothing like enough for firefighting. The nearest hydrant may be at the village edge, several hundred metres from a barn conversion or a pair of new dwellings down a track.

The guidance the fire and rescue services work from, the national guidance document on the provision of water for firefighting prepared for the fire and water industries, sets out indicative flow rates by development type. For low-rise housing the figure usually quoted is 8 litres per second available from a single hydrant, rising sharply for larger buildings, commercial floorspace and anything with a substantial fire load. It also sets expectations on hydrant spacing in residential areas, conventionally no more than 150m apart with a hydrant reasonably close to each entry point. Check the current edition rather than relying on remembered numbers, because the document is revised.

Three things then go wrong in sequence. The water undertaker confirms the mains cannot deliver the flow. The fire and rescue service objects or asks for an alternative source. And the site has no obvious place to put one, because the track is too narrow for an appliance to reach whatever you propose.

Mains capacity and the flow rate a hydrant must deliver

Start with a written flow and pressure test from the water undertaker at the nearest existing hydrant, or a desktop capacity statement for the main that would serve a new one. That is the document that decides the whole question, and it costs very little to obtain at feasibility stage.

Where the main is adequate, the solution is a new hydrant. Under the Water Industry Act 1991 the undertaker has duties around providing fire hydrants, and the fire and rescue authority has its own functions under the Fire and Rescue Services Act 2004 for securing water supplies for firefighting. In practice the developer funds the hydrant installation through the undertaker's developer services route, and the asset is then maintained as part of the network.

Where the main is not adequate, upsizing it is occasionally viable over a short distance and almost never viable over a long one. The cost of several hundred metres of new main in a public highway, with the street works and reinstatement that follows, usually exceeds the cost of a tank by a wide margin.

Static tanks, ponds and open water

Approved Document B deals with this directly in its provisions on access and facilities for the fire service. Where there is no piped water supply or it is inadequate, it points to other sources: a charged static water tank of at least 45,000 litres, a spring, river, canal or pond capable of providing or storing that quantity of water throughout the year, or a swimming pool or other adequate body of water.

Those words do real work on a rural site.

A charged tank is the predictable option. It is buried or bunded, fitted with a suction connection the appliance can couple to, kept full by the mains at a trickle rate rather than at firefighting rate, and positioned where an appliance can stand next to it. Capacity above the minimum is sometimes asked for where the development is larger or where a thatched or timber-framed building is involved.

A pond or watercourse is tempting on a farm and harder to rely on. The test is availability throughout the year, which means the fire and rescue service will want evidence that the water level holds in a dry summer, that the draw-off point is accessible in winter mud, and that the depth at the draw-off allows a hard suction hose to be used without picking up silt. A seasonal pond fails. A pond that depends on a landowner's goodwill in ten years' time also fails, which is why a planning condition is the usual mechanism.

An existing swimming pool in the same ownership rarely survives scrutiny, because nothing stops it being drained or filled in.

Getting a pumping appliance to the source

The water source is only useful if an appliance can reach it. Approved Document B sets out the dimensions a pump appliance needs, and on a rural track they are the binding constraint more often than the tank itself. The figures to design to include a minimum road width between kerbs of 3.7m, a narrower minimum at gateways, a turning circle in the order of 16.8m between kerbs, a clearance height of 3.7m and a carrying capacity of 12.5 tonnes. High reach appliances need more of all of it.

Two consequences for a rural layout. First, a gravel track with soft verges and a 3m pinch point at the gate will not take a loaded appliance in February, so the access needs a bound or reinforced construction over at least the relevant length. Second, there must be somewhere to turn, because reversing a pump appliance several hundred metres down a single-track lane is not a plan.

Position the source so the appliance can stand on hardstanding with the suction lift within the manufacturer's limit, conventionally a short vertical lift rather than a long one, and so that the standing position does not block the only route in for a second appliance.

Talking to the fire and rescue service

The fire and rescue service is consulted on planning applications in its own right, and separately through the building control route. On a rural scheme it is worth approaching the service's water officer or fire safety team before the application goes in, with a plan showing the proposed source, the appliance standing position, the access width and the surface construction.

Where a building crosses the threshold for a fire statement, the planning route changes. Article 9A of the Development Management Procedure Order 2015 requires a fire statement with applications for relevant buildings, and the Building Safety Regulator within the Health and Safety Executive is the Gateway One consultee. Very few rural schemes reach that threshold, and the question of what to do when a building sits just below it is covered in fire evidence for a building just below the threshold.

Below the threshold you are not producing a fire statement for planning purposes, but a short water supply note with a drawing answers the consultee response before it is written.

Conditions that secure the provision

Expect a condition. The standard form requires details of the firefighting water supply and the appliance access to be submitted to and approved by the local planning authority before development begins, with the approved works completed before first occupation.

Two drafting points are worth pushing on. Ask for the condition to be tied to the submitted drawing where you already have one, so you are not paying to redesign something the consultee accepted. And check whether the condition requires completion before occupation of the first dwelling or the last, because on a phased rural scheme the difference matters.

Where a fire safety strategy is being produced for the building itself, the water supply provision should be referenced in it rather than treated as a separate planning afterthought. A fire safety strategy is a fire-engineering document and a competent professional is legally required for it. The same is true of a fire statement where one is needed. An AI-assisted draft is a starting point for that professional, never a substitute.

Who maintains it afterwards

A mains hydrant becomes the undertaker's asset. A private static tank does not, and that is the part that gets forgotten.

Somebody has to check the tank is full, that the suction connection works, that the hardstanding has not been colonised by a hedge and that the access gate is not padlocked. On a single dwelling the owner holds that duty. On a small scheme it belongs in the management company documents alongside the private drive and the drainage. Where the source is a pond on land outside the application site, the obligation needs an easement or a section 106 undertaking, because a condition cannot bind land the applicant does not control.

Supply capacity is also worth recording in the water supply assessment if the scheme is producing one, since the same undertaker correspondence answers both the domestic and the firefighting question.

This is general guidance, not legal advice. Check the position with your local planning authority, the fire and rescue service for the area and a qualified fire engineer before relying on it.

To see which fire, water and access documents a rural site is likely to need, enter your postcode on PlanScope and work through the guided questions. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.