Water neutrality

Water neutrality – a fine balance for developers and house-builders

11 August 2022 By

For an Atlantic-facing island with an international reputation for grey skies, frequent showers and soaking rain, the UK must come to terms with the surprising challenge of managing its wet stuff very carefully over the next few decades … or risk running out of guaranteed clean water.

However, as I hope to show in a moment, through extensive water-related experience as environmental consultants and planning consultants with local authorities, plus a combination of advanced tools and technology, we can deliver the relatively new concept of a net-zero water footprint … with extra cash and carbon savings to boot!

Water and nutrient neutrality working together

The UK building and construction industry, already under considerable pressure to meet the strict requirements of ‘nutrient neutrality’, is now being pressed to prepare for ‘water neutrality’ too.

The national goal is, firstly, to minimise domestic water consumption, secondly reuse recycled water wherever possible, and, finally, offset any remaining water demands locally if goals one and two are not enough.

Too much or too little water in the wrong places at the wrong time

From birth, we tend to take water for granted in the UK. Yes, we moan about it regularly. But wellies, macs and muddy paws are central to many British lifestyles and our sense of identity.

Worryingly, severe flooding is now increasingly common across the UK as the atmosphere warms and our national and global climate becomes less stable. At the same time, rising temperatures rather perversely also raise the likelihood of drought conditions.

Unfortunately, the two do not automatically balance out, and combined with demographic and practical technical pressures, Britain is looking at a long-term strategic drinking water shortfall

More optimistically

The positive news is that by controlling domestic water-use, installing water-efficient appliances and systems, plus with green technology and better surface water management, can lower both nutrient- and water-profiles.

Another crucial advantage of water neutrality is that lowering river and groundwater source abstraction levels also significantly reduces negative impacts on the environment.


At this point I should mention that as an independent multi-disciplinary environmental consultancy and planning consultancy experienced in producing detailed environmental impact assessments (EIA) and flood risk assessments, Enzygo (www.enzygo.com) understands water supply and wastewater disposal planning and environmental permitting regulations and we regularly resolve water-related issues that can affect neutrality.

Our specific aim is to help developers structure the requirements, opportunities, and delay-risks of both water- and nutrient neutrality into their early stage thinking so optimum solutions become part of all local plans, neighbourhood plans, and development management planning applications.

The statistical case

Population growth, climate change, and an ageing water infrastructure are putting pressure on the UK’s potable water supplies. Usage figures and housing targets underline the basic problem.

With Government plans to build an extra 300,000 new homes every year, finding – and treating – the extra 300 billion m3 needed every 12 months presents a major headache for utility companies (https://commonslibrary.parliament.uk/research-briefings/cbp-7671/).

For the record, only 216,000 homes were built in 2021, in part because of Covid-19. This was lower than the 2020 total of 243,000. (https://www.gov.uk/government/statistics/housing-supply-net-additional-dwellings-england-2020-to-2021). But house-building is a national priority.

daily water use

Delving deeper into the data, the Energy Saving Trust (https://energysavingtrust.org.uk/) estimates that each of us uses some 142 litres of water daily – a household average of 349 litres. Another source puts this at 120 litres per person per day (120l/p/day), or 288 litres per household.

To lower growing demands, some authorities are now thinking of setting a water-efficiency target in their planning policies of 100l/p/day for new homes – or even 85l/p/day and 62l/p/day.

This is where well-informed design and planning, extensive sector experience, plus co-operative links with local planning officials, become very important in achieving good practical outcomes.

No long-term short cuts

At the moment, developers can make water use improvements themselves. Or they can buy water offsets, which are effectively the purchase of someone else’s water-efficiency measures in the same local area.

But a key point emerging from the data is that greater water-efficiency alone will not be enough to keep pace with future demand; more fundamental changes are needed. In other words, while fixing supply network leaks is important, simply giving consumers more water to waste is not the aim!

However, the flip side is that if local plans do no more than adopt the water-efficiency targets set out in building regulations, developments will need more offsetting to achieve water neutrality.

To square this awkward circle, developers will have to make and implement important progressive decisions in the next two decades as the new requirements bite.

Tougher planning rules ahead

Water neutrality should be achieved as part of Local Planning Policy with the retrofitting of water-efficient devices in existing housing stocks. However, for new developments the onus will be developers to justify where and why this is not possible.

Only exceptional circumstances will be exempted and applications will fail if they do not prove conclusively that a proposed development will not increase potable water abstraction above existing levels – and preferably reduce it.

Habitat requirements

Some types of permitted development that include prior approvals may also need approval under Section 77 of the Habitats Regulations to show proposals will not have an adverse effect.

The following link on the Habitats Regulations Assessment (HRA) indicates that at a strategic level Natural England (NE) will be involved here, as it is with the nutrient neutrality assessments (https://www.horsham.gov.uk/__data/assets/pdf_file/0011/106769/Horsham-LP_Water-Neutrality-Tech-Note_P5.pdf#:~:text=A%20water%20neutrality%20assessment%20has%20been%20undertaken%20to,methodology%20and%20results%20of%20the%20water%20neutrality%20assessment).

Another useful reference is the Environment Agency’s “Water stressed areas – 2021 classification” (https://www.gov.uk/government/publications/water-stressed-areas-2021-classification).

Achieving water neutrality

Achieving water neutrality

Meanwhile, individuals and businesses can shrink their footprints to become water neutral through three routes: –

– Reducing water use – To help cut total demand developers will be expected to design new homes in ways that encourage water-saving behaviour while also installing water-efficient products and fittings. A building with a smaller demand means that less water needs to be reused and offset later.

Examples include using: – aerated taps and shower heads; low-flush or air-flush toilets; water-efficient washing machines and dishwashers, waterless toilets, recycling showers, and waterless washing machines.

Changing behaviours also means not leaving taps running while brushing teeth; using eco-settings; installing garden water butts; and fitting smart devices to track and show consumers their usage and cost patterns.

greener on the other side
– Note – greener on the other side

Gardens will actually play a key role in water neutrality and there is particularly welcome good news for proud lawn owners.

One school of thought is that grass turning brown when roots no longer absorb nutrients from the soil is part of grass’ natural life cycle. Letting it do so helps to prevent water shortages and dry rivers.

The other line of thinking is well-expressed by the UK Lawn Care Association (Watering Your Lawn Advice – https://www.uklawncare.net/lawn-maintenance/watering-your-lawn-advice/).

It says watering lawns in hot dry weather is important not just to keep them green and healthy but because the thousands of individual grass plants involved remove carbon dioxide from the atmosphere. Lawns are part of the solution, it adds, not the problem.

– Reusing water – This involves the capture and use of alternative water supplies for non-potable uses: – rain and surface water ‘harvesting’; plus recycled grey water from baths, showers and hand basins. Flushing toilets account for 24% of wasted water in the home,  and 4% in the garden.

– Offsetting demand locally – Water that cannot be replaced by alternative sources may be offset in the same local water area. One option here might be to retrofit water-efficient and reuse systems in existing properties, with the caveat is that this must completely offset any additional mains use.

Water resources on BBC Countryfile

Pressures on England’s water resources featured on BBC One’s Countryfile on 15th May 2022 (https://www.bbc.co.uk/programmes/m0017gl7). The programme noted that recent predictions warn that with no further action, an extra 4 billion litres of water daily will be needed to meet demand by 2050 (https://www.countryfile.com/news/water-shortage-in-the-uk-whats-the-problem-and-how-to-save-water/).

Environment Agency CEO Sir James Bevan said the UK must reduce its water use in part by minimising pipework leakages, but also cutting personal consumption. We also need to increase supplies by building more reservoirs and desalination plants that turn sea water into drinking water.

Another option is to move to water across the country from areas of plenty to areas of scarcity, and particularly between contiguous water catchments and networks.

Water neutrality in 3,000 new homes

The UK water services regulator Ofwat is also actively leading the water-neutrality revolution.

As part of its first Water Breakthrough Challenge for utilities that include ‘new entrant water companies’ (NAVs) (https://waterinnovation.challenges.org/breakthrough/), Affinity Water (https://www.affinitywater.co.uk/) was granted £2.9 million in September 2021 to deliver sustainable water-saving solutions on three new housing developments.

The project was described as a “world first” in bringing technologies together; each was previously used individually but not collectively at a scale needed to kick start water neutrality across the UK.

Affinity delivers circa 950 million litres daily to Home Counties and South of England customers. It says population growth forced up demand in the last two years by 24.5 million litres. The Office for National Statistics expects the UK population to reach 72 million by 2041, a 7.8% increase from 2019.

Triple aim

The project is spread across three groups of 1,000 homes to avoid planning-related obstacles and test different approaches at different sites to quantify their impacts accurately.

Its first group has focussed on technology in residential homes: – water-efficient shower heads and washing machines; water-saving tap fittings; rainwater harvesting; and toilet overflow alarms.

The second site looked at community-based approaches – grey-water and commercial-grade toilet systems in non-residential buildings – plus how community liaison officers can change customer behaviour.

The third used a hybrid-solution from the first and second to understand the impact of both at scale, whether either alone can provide the necessary benefits, or if both are required.

Digital window

Residents can also monitor their water consumption via a bespoke app that layers technology data from multiple-sources into a single customer view of water usage. The app is also designed to give a behavioural ‘nudge’ and make remote device monitoring and preventative maintenance possible.

saving water

The project’s overarching goal includes saving more than 336 million litres of water in all the targeted homes. Carbon savings equivalent to around 107 tonnes of CO2 per year are forecast, and annual water and energy bill savings of circa £44 per home.

Water v nutrient neutrality

As a footnote, I must emphasise that water neutrality is an established issue which is rapidly becoming more important as water stresses grow across some parts of the country.

As a background reference, the Environment Agency first looked at water neutrality implications for the Thames Gateway in 2009 (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/291668/scho1107bnmc-e-e.pdf).

It should not be confused with the important issues of nutrient neutrality which I looked at in “Nutrients neutralise new development in England” (https://www.enzygo.com/hydrology/nutrients-neutralise-new-development-in-england/) and “Floating new ideas for nutrient-neutral home-building” (https://www.enzygo.com/news/floating-new-ideas-for-nutrient-neutral-home-building/).

However, the two ‘neutralities’ are linked because over-abstraction, and, for example, compensation flow cuts downstream of reservoirs, can increase nutrient concentrations … and so the nutrient problem.

I hope this brief introduction into an issue that will inevitably become increasingly important in the very near future has been helpful.

As always, if you would like more information about our environmental services, or want to discuss any of the points raised, please contact me directly.

Dr Paul Hardwick, Technical Director, Enzygo Ltd

See the LinkedIn article – linkedin.com/pulse/water-neutrality-fine-balance-developers-house-builders-/?trackingId=RSFT%2BUsIaL1%2B2ZbB4JqITg%3D%3D