Groundwater abstraction and development near a borehole

An abstraction licence development borehole question usually starts with a farm wanting to put a new use on land served by its own water supply, or a neighbour worried that a new scheme will take their water. Two regimes answer it, and neither of them is planning.

Abstraction is licensed by the Environment Agency under water resources legislation, with a threshold of 20 cubic metres a day below which no licence is needed. Private water supplies are regulated by the local authority's environmental health team for quality. The planning system controls neither, and that limits what a condition on your permission can usefully do.

What planning does control is the development: where the foul drainage goes, what the ground is used for, and whether the proposal creates a risk to a supply that already exists.

Abstraction licensing and the thresholds that apply

An abstraction licence from the Environment Agency is required to take more than 20 cubic metres a day from a surface source or from groundwater. Below that figure the abstraction is exempt, which is why most single farmhouse and single-dwelling boreholes operate without a licence.

The 20 cubic metre threshold is the one to test your proposal against, and the arithmetic catches people out. A borehole serving a farmhouse and a couple of cottages sits well below it. The same borehole asked to serve a campsite with shower blocks, a farm shop with food preparation, a livery with 30 horses or an irrigated field crop can exceed it quickly.

Licence types differ by purpose. Full licences cover ongoing abstraction, transfer licences cover moving water between sources without intervening use, and temporary licences cover short periods. Dewatering for construction became licensable in its own right following reform of the exemptions, so a basement or deep foundation scheme that lowers groundwater needs its own authorisation, which is a different consent again.

Catchment availability governs whether a new licence is realistic at all. The Environment Agency publishes abstraction licensing strategies by catchment, stating whether water is available for new licences at different flow conditions. In a catchment classed as having no water available, a new licence for a consumptive use is unlikely, and that is a constraint on the development rather than a detail to resolve later.

Protecting a neighbouring private supply

The relationship between a new abstraction and an existing one is the part most people get wrong.

Water resources legislation protects what it calls protected rights. Those include abstraction under an existing licence and the right of an occupier of land contiguous to inland water to take small quantities. The Environment Agency must not grant a licence that would derogate from a protected right, which means a new licensed abstraction cannot lawfully be permitted where it would take water away from a protected existing abstractor.

The gap in that protection matters here. An unlicensed abstraction below the 20 cubic metre threshold, taken from groundwater rather than from contiguous inland water, may not be a protected right at all. So a neighbour drawing 15 cubic metres a day from a borehole for a farmhouse and holiday cottages may have no statutory protection against a new licensed abstraction nearby.

That is an uncomfortable position and it is worth stating plainly rather than glossing over. Where a supply matters, the practical responses are a private law agreement with the neighbouring landowner, a monitoring and make-good arrangement, or an application for a licence that converts the abstraction into a protected right.

Derogation claims and how they arise

A derogation issue shows up as a falling water level, a reduced yield or a dry borehole, usually after a new abstraction starts or after an existing one increases.

Establishing it needs baseline data, which almost nobody has. The evidence that persuades is a record of water levels and yields from before the new abstraction began, a hydrogeological assessment linking the two boreholes through the same aquifer unit, and pumping test data showing the drawdown cone reaching the affected well.

So the useful advice is preventative. Where a development will rely on or sit near a borehole supply, start monitoring now. A datalogger in the borehole recording rest and pumping water levels for twelve months before anything changes costs very little and is the difference between a provable claim and an argument.

The same logic applies in reverse. A developer who has monitored the neighbouring supply before starting work is in a much better position when a claim arrives.

What a council can and cannot control through planning

A planning authority cannot grant or refuse an abstraction licence and cannot regulate how much water you take. What it can do, and routinely does, is condition the development.

Conditions that are within the council's power and that do genuine work:

• Details of the water supply arrangement for a new use, to be submitted and approved before occupation, including the source and the expected demand.
• Details of foul drainage, which is where the real risk to a supply usually lies.
• A scheme of borehole monitoring during construction where dewatering or deep excavation is proposed.
• Restrictions on the use of land within a defined distance of a wellhead, such as no storage of fuel, slurry or silage.
• Surface water drainage details preventing direct discharge to the aquifer in a sensitive setting.

A Water Supply Assessment covering the source, the yield, the water quality position and the forecast demand answers the first of those before an officer asks. Where the Environment Agency is consulted, it will comment on the abstraction position and on groundwater protection rather than on the planning merits.

Source protection zones are a related but separate constraint. The Environment Agency defines inner, outer and total catchment zones around public supply abstraction points, and development within the inner zone attracts restrictions on activities that could pollute groundwater. A private borehole does not generate a source protection zone, which is why the 50 metre separation rules discussed in groundwater abstraction points and the 50 metre rule do the protective work for private supplies instead.

Evidence on water availability for a new use

For a diversification scheme the water question needs answering with numbers rather than with an assumption that the existing borehole will cope.

Set out the demand first: the use, the occupancy, the daily consumption per head or per unit, and the peak day. Then set out the supply: the borehole's tested yield, the pump capacity, the storage volume and the recovery rate. Then compare them, and state whether the result sits below or above the 20 cubic metre licensing threshold.

Where the figure goes above the threshold, say so and explain the licensing route and the catchment availability position. An application that quietly implies a new campsite will be served by an unlicensed borehole invites the Environment Agency to object.

Where the supply is marginal, the options are mains connection, where one is reachable, additional storage to even out peaks, a second source, or reducing the scale of the use. Mains connection costs are highly site-specific and the water undertaker will quote, so get the quote before the appraisal rather than after.

Water quality is the local authority's concern under the private water supply regulations, which require risk assessment and sampling. A new commercial use served by a private supply will be brought into that regime, and the cost of treatment to reach drinking water standards is a real item in the business plan.

Drainage and foul disposal near a supply

This is where most development near a borehole actually fails, and the rule is specific.

Under the general binding rules for small sewage discharges to ground, a drainage field must be at least 50 metres from any well, borehole or spring used for drinking water supply, at least 10 metres from a watercourse and at least 15 metres from any building. A septic tank discharging to a drainage field within 50 metres of a borehole is not permitted, and no planning permission changes that.

On a tight rural plot with a borehole, those separations frequently cannot all be achieved, and the scheme then needs a package treatment plant with a surface water discharge, a sealed cesspool with tankered removal, or a connection to a public sewer. Each has a cost and a consent of its own.

Work the drainage layout before the house position is fixed. A Foul Sewage Assessment showing the separations on a dimensioned plan is the quickest way to close the point with both the council and the Environment Agency.

Historic contamination deserves a look too, since a borehole in an aquifer beneath a former farmyard, fuel store or sheep dip has a plausible pollutant pathway. Where the site history suggests one, a desk study comes first, and PlanScope's draft of a land contamination assessment is a starting point for the suitably qualified and experienced person who must prepare it rather than a substitute for them.

Conditions and monitoring

The condition set worth offering on a scheme of this kind covers water supply details including source and demand, foul drainage details with the separation distances demonstrated, a construction method statement addressing groundwater where excavation is deep, borehole water level monitoring before, during and after construction where a neighbouring supply is at risk, and a restriction on polluting activities within a stated radius of any wellhead.

Volunteering the monitoring condition is the move that most often settles a neighbour's objection. It costs little, it produces the data that would resolve any later dispute, and it demonstrates that the risk has been taken seriously rather than denied.

One honest uncertainty: whether a particular unlicensed abstraction amounts to a protected right turns on facts and on the source, and it is a question for a water lawyer or hydrogeologist rather than for a planning statement.

This is general guidance, not legal advice. Check the position with your local planning authority, the Environment Agency or a qualified professional before relying on it.

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