Water efficiency must be considered alongside housing delivery

Housing delivery is firmly on the political agenda, driven by the UK government’s target to build 1.5 million homes over the course of the parliament.

A parallel issue is also emerging: hot water efficiency. As policymakers look to unlock housing growth, the question is no longer simply where homes can be built, but whether local infrastructure can sustainably support them.

In fact, the government’s own position is that stronger water-efficiency standards are vital to help “unblock” housing delivery in water-stressed areas. As The Department for Environment, Food and Rural Affairs states: “a failure to implement water demand management measures in response to water scarcity could result in over 61,000 houses not being built, costing the economy £25 billion.”

With over 70% of England now in drought due to the ongoing dry and hot summer, water scarcity is becoming front of mind with over 27 million facing water use restrictions.

In response to growing concerns, the government ran a consultation last year on proposed changes to Approved Document G of the building regulations - the rules governing sanitation, hot water safety and water efficiency – suggesting, among other things, ways to reduce water use in new homes.

This proposes tighter requirements for designed water use and sets out the potential for more stringent standards in areas facing serious water stress. The consultation proposed reducing the mandatory average water use limit for new homes from 125 litres per person per day (l/p/d) to 105 l/p/d, alongside a tighter optional standard of 100 l/p/d in areas of serious water stress.

The industry is therefore entering an era where inefficient water use may directly affect how many homes can be delivered and where they can be built.

With over 70% of England now in drought due to the ongoing dry and hot summer, water scarcity is becoming front of mind

At a time when the sector continues to face financial challenges, with a BCIS report forecasting a 13% rise in build costs over the next five years, it may be tempting for some developers to adopt a minimum compliance approach to manage costs and maximise profit margins. For example, developers might take an approach of installing restrictor valves to meet regulations or install low-flow showerheads or inline flow restrictors.

The problem with these approaches is that they don’t account for user behaviour.

Our research has found that users find a 6L/min flow highly frustrating, which can lead to homeowners replacing their flow restricted showerhead with a high flow alternative, seeking a more powerful shower. If a developer has sized the drainage and pipework for a low-flow system, the new high-flow shower can overwhelm the shallow-tray waste traps, leading to bathroom flooding and causing leaks. This in turn can lead to reputational damage for developers, as well as operational risks.

If water availability is becoming a limiting factor on where and how many homes can be built, the industry needs solutions that deliver genuine reductions in water demand, not just compliance on paper. This includes moving beyond solutions that simply restrict flow.

What matters is not the specification on a product datasheet, but the overall water demand created by a development once people move in. As water scarcity increasingly influences housing delivery, developers will need approaches that provide confidence in real-world performance, helping ensure that every litre saved contributes to unlocking future growth.

Water efficiency labels are another compliance tool, serving to bridge regulatory standards and consumer behaviour by verifying product performance. It will undoubtedly play an important role in helping consumers and specifiers identify more efficient products, bringing greater transparency, and consistency to the market.

Research has shown that most consumers are likely to choose a water-efficient product when clear labelling is available, making labels a valuable tool for influencing purchasing decisions. However, labels alone will not solve the UK’s growing water challenge. They provide information about the performance of individual products, but do not address how water is used across the home, or the interaction between water consumption, energy demand and occupant behaviour.

If the industry is serious about supporting housing growth in water-stressed areas, water efficiency must be considered as part of a wider system of design decisions rather than relying solely on product labelling to drive meaningful reductions in demand.

If water availability is becoming a limiting factor on where and how many homes can be built, the industry needs solutions that deliver genuine reductions in water demand

Technologies such as waste water heat recovery for showers demonstrate how reducing water consumption and reducing energy consumption can go hand in hand. Yet there is growing concern that future compliance pathways may place greater emphasis on energy generation technologies alone, such as solar panels, potentially overlooking proven demand-reduction measures that deliver consistent savings throughout the year.

This is why product-level interventions alone are unlikely to give developers the certainty they need. If shower performance and hot water demand are not considered together from the outset, developments can be forced into reactive system design, from larger cylinders and higher backup loads to greater reliance on immersion heaters. Each adds cost, complexity and carbon, without addressing the underlying question of whether the home will perform efficiently once occupied.

A more viable approach is to design around real-world water use: setting clearer expectations for shower volumes, performance and duration, and taking a systems thinking approach to specifying hot water that can deliver efficiency without compromising the user experience. For developers operating in water-stressed areas, this joined-up thinking is no longer just a sustainability consideration, it is becoming central to whether schemes can be delivered affordably, compliantly and at scale.

Water efficiency and energy efficiency are often discussed separately, but hot water is one of the largest energy demands in the home and therefore must be considered at the outset. If developers cut corners to meet regulation, then they risk the need for costly retrofits later down the line. As homeowners become increasingly more environmentally conscious, and pressure on water systems continues to increase with global warming, it is vital that developers consider water efficiency from the outset. This will ensure builds are viable both now, and in the future.

Suzannah Adey is external affairs and ESG lead at Mira Showers