Why water efficiency matters in constructions

Whilst there are many reasons why we should increase the water efficiency of new housing developments, two of the most significant reasons are:

Lowering water consumption

The region in which Cambridge Water operates is classed as an area of serious water stress.

The east of England is not only the fastest growing region in England, it’s also the driest. As the climate changes, without a fundamental rethink of how we use and share water in this part of the UK, there won’t be enough to meet current demands, let alone the growth planned for this area.

Cambridge Water has collaborated with Anglian Water, Essex and Suffolk Water and Affinity Water on a joint initiative developed by Natural England and the Environment Agency to create the Shared Standards in Water Efficiency for Local Plans.

The plan sets out how we can secure higher water efficiency standards for new homes and for commercial developments.   

Reducing developer bills

Developer customers have an opportunity to reduce their bills by attracting discounts and rebates that we provide for water efficient building.

Cambridge Water operates an incentive scheme which is designed to promote water efficient home building by providing discounts/rebates against the infrastructure charge when developers employ one of the options set out below to reduce consumption in newly connected properties.

Water efficiency options

Discount level

The discount provided for any option will be based on the reduction in consumption demonstrated within the design information put forward with each application.

A sliding scale will be used, shown below, where the discount will reflect 100% of the infrastructure charge when properties are designed to meet 80lpd.

However, greater and lesser discounts can be achieved by scaling up or down the consumption reduction.

Discount sliding scale example

What is the process?

Step 1- Application

We need to know that you intend to build water efficient homes at the application stage.

When you submit your application, select the relevant option which notifies us that you are planning to build qualifying water efficient homes. There are a few short additional questions to answer at this stage to provide us with more information.

Step 2 - Working out the discount

You’ll need to submit evidence to us that demonstrates the level of reduced consumption.

This could be:

• Home Quality Mark (HQM)
• BREEAM certification
• Another appropriate accreditation
• Product specification information alongside evidence of real-world use/savings

Where developments are opting to achieve savings through internal fittings, we often receive outputs from a water calculator, such as the example shown below. This is also acceptable evidence.

Step 3 - Demonstrating the expected consumption

We need to be able to substantiate the savings expected. We do this at the application stage by reviewing documentation which evidences the expected consumption.

Most typically, this is in the form of product or supplier specification information. 

Consumption evidence can take different forms, particularly when relating to harvesting systems or water neutrality. If you have other forms of evidence, please speak to us when submitting your application.

We also use the substantiation evidence when completing the site audit part of the process, by matching the images on the substantiation with the fitting or device we see on site.

Once steps 1, 2 and 3 are complete, we will use the consumption total to calculate the discount/rebate and apply this to the infrastructure charges within the quote we provide to you.

Reviewing on a case-by-case basis

We recognise that each option (internal fittings, flow restrictors, harvesting devices etc.) is better suited to some scenarios and less suited to others. For example, reducers might not be suitable in areas of our network with lower pressure.

We will therefore review each application on a case-by-case basis.

We also need to ensure that, where options are implemented, the necessary controls are in place – such as non-return valves on harvesting systems. This will also be done on a case-by-case basis, at the design stage.

Auditing the site and applying the discount/rebate

We will agree to any discount/rebate in advance of the connection stage, provided the qualifying criteria has been met. 

After this, a site-based audit will need to be conducted before the discount/rebate is provided. There is a charge for this audit. 

In April 2025, Ofwat introduced the Environmental Incentives Common Framework. 

In line with this, water companies:

• must only audit completed properties (when all fittings relevant to the qualifying criteria for the environmental incentives are installed); and
• must not audit occupied properties

Any water efficiency audit must be requested before properties are occupied. We ask for a minimum of two weeks' notice is provided to us to arrange this. 

For further information, such as our audit charge, our approach to auditing, and what happens if the site devices do not match the original substantiation, please read chapter 13 of our Charging Arrangements.