What are Heat Pumps?

Heat pumps operate by taking the latent heat from air and water sources and boosting the temperature using electrically driven pumps. The resultant hot water can be fed into local heat networks or single buildings, providing a low-carbon source of renewable heat to local areas. Heat Pumps can also be used for cooling by removing warm air from the property.

Types of heat Pumps

Air Sourced Heat Pump

An air source heat pump extracts air from outside warming a refrigerant, which is then circulated around the home providing heating and hot water.

NRW have no role in the installation and operation of Air Sourced Heat Pumps.

Water Sourced Heat Pumps (including Ground Sourced Heat Pumps)

Water Sourced Heat Pumps use water from a range of sources, including rivers, canals, lakes, abandoned mines, the sea and groundwater aquifers. This type of heat pump can be “closed loop” or “open loop”.

In an open loop system, water is abstracted from the water source and passed through a heat pump before being discharged back into the water source.

In a closed loop system pipes or heat exchange panels are placed in the ground or watercourse and a water/antifreeze mixture is passed through the pipes absorbing heat from the water.

Potential Environmental Effects

All heat pumps systems can also result in undesirable temperature changes in the water environment with impacts on water quality or aquatic ecology, however, these risks can be mitigated.

We encourage GSHC systems that are well-managed and designed to present a low risk to the environment and other users of water.

Download best practice guidance from the GSHC website

Permits and licences required

The permits and permissions you need depend on whether you’re installing a ground heat pump taking water from the ground or a heat pump which takes water from a river, lake or stream.

Permits for surface water source heat pumps

Several permits are potentially required for anybody wanting to install a heat pump which takes water from a lake, stream or river. You may need:

If you have a small surface water open-loop heat pump system and comply with the conditions below you do not need to apply for an environmental permit to discharge the water because Natural Resources Wales considers it to be low risk.

Conditions you must comply with:

  • the system is used to heat or cool a single domestic property
  • the water is abstracted from, and discharged to, the same surface water body, for example a river or stream, and not a lake or pond
  • cleaning chemicals are not discharged to the surface water
  • the property is not used for commercial purposes

An abstraction licence is still required if the system uses more than 20 cubic metres per day.

If your surface water system does not meet these criteria, check if you can apply for a standard rules permit below. If you cannot then you must apply for a bespoke permit.

Standard rules water discharge permits for surface water systems

You may be able to apply for a standard rules permit if you discharge up to 1000 cubic metres of water a day from your heat pump system to surface water.

Applying for a standard rules water discharge permit is usually quicker and may cost less than a bespoke permit.

You must be able to comply with all the conditions of the permit.

If you do not meet the conditions for the standard rules permit you must apply for a bespoke permit.

Before you apply for a standard rules water discharge permit

Before applying for a standard rules permit:

Contact us if you want advice or help with your application.

When to apply for a bespoke water discharge permit

You must apply for a bespoke permit for the discharge if you have an open-loop surface water system that does not meet the conditions above.

When to apply for an environmental permit for a flood risk activity

You must apply for an environmental permit for a flood risk activity if any part of your planned scheme involves construction:

  • in, under, over or near a main river (including where the river is in a culvert)
  • on or near a flood defence on a main river or set back remotely from it
  • in the flood plain of a main river
  • on or near a sea defence

Read more about applying for a flood risk activity permit and find out if you’re near a main river

If you’re carrying out work to an ordinary watercourse rather than a main river, you do not need an environmental permit for flood risk activities. You may need to apply for a land drainage consent from either your local council or internal drainage board if you have one.

Find your local authority

Read more about internal drainage boards and if you have one

Ground Sourced Heat Pumps

Anybody wanting to install a ground source heat pump will need:

Closed loop ground source heat pumps do not require any permissions from us because under normal operation they do not introduce pollutants into the aquifer. However, we strongly recommend that these systems use non-hazardous substances to avoid pollution of groundwater in the event of a leak. If leaks occur and pollutants may enter groundwater we can serve notices to prohibit the discharge or require a permit.

Ground source open-loop heat pump systems: exemptions

The following ground source heating and cooling system are exempt from needing an environmental permit for the water discharge:

  • a cooled aquifer system with a volume of less than 1,500 cubic metres per day
  • a balanced system with a volume of less than 430 cubic metres per day
  • a heated aquifer system with a volume of less than 215 cubic metres per day

You must register and be able to meet the conditions of the exemption.

Conditions of the exemption

To be eligible for the exemption the following conditions must all apply.

The system:

  • will discharge water at a temperature that will not exceed 25°C and will not vary by more than 10°C compared to that in the aquifer from which it was abstracted.
  • is not on a known contaminated site or one where contaminating activities used to take place – contact your local council to find this out.
  • will abstract and discharge within the same aquifer.

The water within the system:

  • will not have anything added to it – for example additives used for descaling.
  • will not be used for any other purpose.

The system will not discharge water within any of the following:

  • 50 metres of a watercourse or a groundwater-fed wetland (for example site of special scientific interest) – contact us to find this out
  • 50 metres of any groundwater abstraction (for example borehole, well or spring) used for any purpose
  • Source Protection Zone (SPZ)that’s used to supply water for domestic or food production purposes

You will need to check with the owners of neighbouring properties to find out if they have a private water supply or other type of abstraction.

Bespoke permit

A bespoke permit is required if these conditions cannot be met.

This exemption is just for the environmental permit for water discharge, an abstraction licence and groundwater investigation consent are still required.

Groundwater investigation consent

A Groundwater Investigation Consent is needed to investigate a groundwater source before you drill or test pump any abstraction boreholes. This consent allows somebody to find out what water is available and whether it’s suitable for their needs.

Read more about applying for groundwater investigation consent

Boreholes, wells and excavations must be designed, constructed and decommissioned in such a way that prevents groundwater pollution.

If the system allows for the reversal of flow (so that the discharge point becomes a point of abstraction) groundwater investigation consent will be required for all boreholes.

The British Geological Survey must also be notified before drilling any new boreholes.

The results of this investigation should be used to produce a groundwater impact assessment to submit with any future abstraction licence application. 

Abstraction Licence

After finishing investigations a water abstraction licence is required to continue to abstract groundwater if removing more than 20 cubic metres per day from groundwater. Please note that even if the source provides enough water, this does not mean a licence will automatically be granted.

Read more about applying for a water abstraction licence.

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