Borehole Water Supply | How It Works and Suitability Guide

What is a borehole water supply?

A borehole water supply is a private water source created by drilling to an underground aquifer and pumping groundwater directly into your property. It replaces the need for a mains connection by giving you access to the natural water stored beneath your land.

The groundwater itself has travelled through layers of chalk and rock, which act as a natural filter. This produces clean mineral-rich water that can be used for drinking, washing and general daily use.

A borehole system is built using specialist drilling equipment and a high-efficiency pump that lifts the water to the surface. Once connected to your internal system, it provides a dependable and independent supply tailored to your location.

How does a borehole work?

A borehole system efficiently extracts potable water from an underground aquifer. When used as a drinking supply, the installation must comply with UK rules, including the water fitting regulations and the Private Water Supplies Regulations.

Below is a clear step-by-step overview of how a borehole system installation works.

Step 1: Site survey and groundwater assessment

A pre-drilling survey identifies where the aquifer sits beneath your property and whether it can provide a sustainable water supply. This usually includes:

Geological mapping
Anticipated depth and yield
Risks from nearby septic tanks or agricultural chemicals
Any restrictions set by the Environment Agency

Many organisations explore boreholes when looking to reduce reliance on a business water supplier or manage rising business water rates. For larger commercial properties, abstraction consent may be required if more than 20 cubic metres per day will be used.

Step 2: Drilling the borehole

A rotary drilling rig creates a narrow shaft to the correct depth based on the geology. Once the aquifer is reached:

A steel or PVC casing is installed around the shaft
A gravel pack is added to stabilise the borehole
The upper section is sealed to prevent contamination

Construction follows standards set out in BS 5930 and good practice guidance from the British Geological Survey.

Step 3: Water quality testing

After drilling, the borehole is flushed, and a sample is taken for laboratory analysis. Tests check for:

Bacteria such as E coli
Nitrates and nitrites
Metals and minerals
pH, hardness and turbidity

If the water is used for drinking, it must meet the Private Water Supplies Regulations. Results guide any treatment equipment needed.

Step 4: Pump design and installation

Once the water quality and yield are confirmed, the installer designs a pump system tailored to the property. This includes:

Submersible pump size
Rising main and pressure settings
Control units and safety features

A test run checks both flow rate and sustainable recharge to ensure the borehole can deliver the required daily supply without breaching water abstraction rules.

Step 5: Water treatment and final setup

Although groundwater is naturally filtered by rock, some sites need treatment equipment to meet drinking standards or protect appliances. This may include:

UV disinfection
Sediment filters
Iron or manganese removal
pH correction

Once treatment is installed, the borehole connects directly into your property’s system to provide a dependable long-term supply.

Where does borehole water come from?

Borehole water comes from groundwater stored in the natural rock layers beneath your property.

These water-bearing layers are known as aquifers. They hold large amounts of clean water that can be accessed by drilling a borehole down to the right depth.

How groundwater forms

Groundwater begins as rain. When it falls, some of it soaks into the ground and slowly travels down through soil, sand, chalk and other permeable rock. These rocks act like a natural filter. As the water moves through them, impurities are removed, and the water becomes very clean.

Eventually, the water reaches a deeper layer of rock that can hold it, called an aquifer. Rainfall continues to replenish this layer over time, ensuring the aquifer isn’t depleted by a borehole installation.

Different aquifers across the UK

The UK has several types of aquifers, and the type you sit on affects the depth of the borehole and the quality of the water. Common aquifers include:

Chalk, found across large parts of southern and eastern England
Limestone, common in the Midlands and the north
Sandstone, found in Wales, the Midlands and the northwest

Each rock type stores and filters water differently, which is why borehole installers check your local geology before drilling.

Why a site assessment is important

Before drilling, a specialist carries out a hydrogeological assessment. This looks at:

How deep the aquifer is
How much water it can reliably provide
How quickly it is topped up by rainfall
Any local factors that could affect water quality

This assessment makes sure the borehole will be sustainable long-term and gives you a clear understanding of what your water supply will be like once installed.

The benefits of a borehole water supply for my business

These are the three most important benefits of using a borehole as a water supply for your business.

Cost savings

Once a borehole water supply is installed, ongoing water costs are minimal, requiring only the payment of business electricity rates for pumping water to the surface

Business water rates increase each year and are more expensive than ever, so securing your own water supply can save thousands by avoiding charges on business water bills.

Supply security

A borehole provides an independent water source that protects companies against business water interruptions.

For businesses such as manufacturing facilities or power plants, where an uninterrupted water supply is vital, a borehole water supply offers a redundancy option in case of issues with the local mains water supply.

Sustainability

The British water industry uses vast amounts of electricity to pump water over long distances through local pipework, resulting in a substantial carbon footprint.

In contrast, sustainable water extraction from local aquifers requires only a small amount of energy.

Costs of a borehole water supply

The installation costs for a water borehole depend on several factors, including the size of the borehole, the quality of the groundwater, and the required daily water supply capacity.

Simple borehole water supply installations start from approximately £10,000. Here is a summary of the different cost components, along with an estimated range for each:

Cost Component	Description	Estimated Cost Range (£)
Site Survey and Feasibility	Hydrogeological surveys to assess water availability, quality, and suitability of the location.	500 - 3,000
Permissions and Licensing	Application fees for abstraction licences from the Environment Agency (if over 20m³/day).	125 - 1,500+
Drilling and Construction	Drilling the borehole, casing installation, and well construction. Costs depend on depth and geology.	6,000 - 25,000+
Pumping System Installation	Submersible pumps, pipework, and necessary fittings to extract water.	2,000 - 8,000
Water Treatment System	Filtration, UV treatment, or reverse osmosis to meet specific water quality requirements.	1,500 - 10,000+
Storage Tanks	Water storage systems for buffering and supply management.	1,000 - 5,000+
Electrical Systems	Wiring, control panels, and integration of pumping and treatment systems.	1,000 - 4,000
Monitoring Equipment	Flow meters, water quality testing devices, and other monitoring systems.	500 - 3,000
Site Restoration	Post-installation landscaping or repairs to restore the site.	500 - 2,000
Total installation	All installation costs above.	10,000 - 50,000
Ongoing Maintenance	Annual servicing, pump repairs, and water quality testing.	500 - 1,500/year

How much water can a borehole produce per day?

The amount of water a borehole can produce varies from site to site, but most UK systems provide far more than a home or small business needs each day. The daily output depends on the aquifer, the depth of the borehole and the design of the pump system.

What most properties can expect

A well-constructed borehole can produce several thousand litres per day.

Many sites easily reach ten thousand litres or more, which is more than enough for homes, farms and small commercial properties.

What affects the daily output

Daily yield is shaped by three main factors:

The aquifer beneath your land
The depth needed to reach the strongest water-bearing layer
The pump design and flow rate settings

These points are assessed before drilling, so you know what to expect before committing to installing a borehole.

How output is confirmed

After drilling, the installer carries out a flow test. This shows:

How much water the borehole can produce
How the water level behaves while pumping
How quickly it recovers once pumping stops

The results confirm the true daily capacity and whether the borehole can support your long-term needs.

When a licence is required

If you plan to use more than 20,000 litres per day (20 cubic metres), the Environment Agency requires an abstraction licence.

This applies mainly to:

Larger farms
Industrial processes
Properties replacing a high-volume mains connection

Most businesses fall well below this threshold, but it is an important consideration for high demand sites.

Who needs a borehole water supply?

A borehole water supply is most useful for properties or businesses that use large volumes of water or want greater control over their supply. While many small sites rely fully on their mains water connection, a borehole can be a cost-effective alternative for locations where daily use is high or where mains access is limited.

Businesses that benefit most from a borehole

Here’s a summary of the types of businesses that typically choose a borehole water supply.

Agriculture and horticulture

Farms, nurseries and growers often use thousands of litres of water a day for irrigation and livestock. Rural locations usually sit above strong aquifers, making a borehole a practical and reliable way to reduce dependence on a business water supplier.

Hotels, holiday parks and golf courses

Sites with large grounds, gardens, laundry facilities and swimming pools can face high business water rates. A borehole provides a steady supply for outdoor maintenance and day-to-day operations at a much lower long-term cost.

Commercial and industrial sites with high water demand

Food production, manufacturing, workshops and other high-use businesses often find a borehole more economical than scaling up a mains supply. Consistent water quality and on-site control are key reasons these businesses explore a private source.

Rural properties and off-grid locations

Homes and commercial buildings in remote areas may not have a strong mains connection. A borehole offers a dependable supply that is not affected by network pressure or local outages.

Is a borehole right for your business

A borehole is worth considering if:

Your site uses large volumes of water daily
You want to reduce long-term reliance on your mains supply
Rising business water rates are affecting your running costs
You operate in a rural area with access to suitable geology
Your business is expanding and needs a more secure water source

A hydrogeological assessment will confirm whether your location is suitable and what the likely daily output will be.

The drawbacks to consider before installing a borehole

A borehole can provide long-term savings and a reliable private supply, but there are some practical considerations to be aware of before deciding if it is the right choice for your property.

Water treatment may be required

Groundwater is naturally filtered, but it does not always meet drinking standards straight from the source. Many sites need treatment, such as UV disinfection or filtration. This adds to the initial cost and requires regular testing to stay compliant with the Private Water Supplies Regulations.

Not every location is suitable

The quality and reliability of a borehole depends on the local aquifer. Some areas have limited groundwater, while others may be affected by agricultural fertiliser pollution or historic industrial activity like landfills. A hydrogeological survey will confirm suitability before work starts.

Over abstraction can cause issues

Taking too much water from an aquifer can lower groundwater levels and affect nearby streams or wetlands. This is why larger sites may need an abstraction licence from the Environment Agency if usage exceeds 20,000 litres per day. A flow test ensures the borehole can be used sustainably.

What regulations apply to borehole water supplies

Borehole water supplies in the UK must meet several regulations to protect groundwater, ensure safe drinking water and manage how much water is taken from the aquifer.

Regulation	What it covers	What it means for your borehole
Borehole construction guidance (BS 5930)	Standards for ground investigation, drilling and safe construction	The borehole must be designed and built in a way that protects the aquifer. This includes proper casing, sealing and choosing a safe location away from contamination risks.
Private Water Supplies Regulations 2016	Drinking water quality, sampling and risk assessment for private supplies	Any borehole used for drinking must be sampled and risk assessed by the local authority. Water is tested for bacteria, metals, nitrates and other parameters to make sure it is safe.
Environment Agency abstraction rules	How much water you are allowed to take from an aquifer	If you plan to use more than 20,000 litres per day, you normally need an abstraction licence. This mainly affects farms, commercial sites and properties replacing a high-volume mains connection.
Planning permission rules	Local authority requirements for drilling and associated structures	Most boreholes do not need planning permission. It may be required for pump houses, buildings, protected land or locations with specific local planning restrictions.
Mandatory risk assessments	Protecting the water source from contamination	A risk assessment is required for any drinking supply. The borehole must be sited away from septic tanks, fuel storage, chemicals and other risks identified by the local authority.
Mandatory water quality testing	Ongoing checks to keep the drinking supply safe	Regular sampling is required under the Private Water Supplies Regulations. The frequency depends on whether the supply is a single home, a rental property, or a commercial site.
Water fitting regulations	Rules governing how water systems are installed	Pipes, fittings and treatment equipment must be installed in a way that prevents contamination and meets the national water fitting regulations. This applies when the borehole connects to internal plumbing.

Borehole water supply FAQs

Our business water experts answer frequently asked questions about borehole water supplies in Britain.

How deep should a borehole be?

The depth depends entirely on the aquifer beneath your property. Some boreholes reach groundwater at thirty to forty metres, while others need drilling to seventy metres or more. A site survey identifies the depth needed before any work begins.

What is the difference between a borehole and a well?

A well is usually a wider opening created by digging or excavation. A borehole is a narrow drilled shaft that reaches deeper water-bearing rock. Both provide groundwater, but boreholes are more common for modern drinking and business use because they reach cleaner, better-protected aquifers.

Is borehole water safe to drink?

Yes, borehole water can be safe to drink, but it must be tested to meet the Private Water Supplies Regulations. Many sites need simple treatment, such as filtration or UV disinfection to make sure the supply meets drinking standards.

Do I need permission to drill a borehole?

Most properties do not need planning permission for drilling, but you may need consent if the work involves a new building, protected land or restricted access. If you plan to use more than twenty thousand litres per day, you will need an abstraction licence from the Environment Agency.

How long does a borehole last?

A well-constructed borehole can last several decades. The casing, pump and treatment equipment may need occasional replacement, but the borehole itself is a long-term asset for your property or business.

Can you drink borehole water without treatment?

Some sites produce excellent quality water, but most supplies still need basic treatment to meet drinking standards. Treatment requirements depend on the laboratory test carried out after drilling.

What if the borehole water smells?

A smell often indicates natural minerals, bacteria or changes in the water chemistry. A water test will identify the cause and the correct treatment, such as carbon filtration or UV disinfection.

What affects borehole water pressure?

Water pressure is shaped by the pump size, the depth of the borehole and the distance to the property. A correctly specified pump system delivers strong, consistent pressure for homes, farms and commercial buildings.