Should Rainwater Harvesting be mandatory in the UK?

It’s 2025. Why are we still flushing toilets with drinking water?

In this week’s blog, we take a look at why mandatory introduction of water reuse technologies is needed and how it can be best achieved.

If you’ve made it here, you probably have a good awareness of rainwater harvesting and greywater recycling. If not, we can bring you up to speed with our “how it works” guide.

With only 25 years to find 5 billion litres of additional water per day, you will know that we have a finite amount of time to make an impact on water conservation. Many buildings which are being designed right now will still be fully operational in 25 years, meaning these buildings must promote water efficiency for years to come.

Despite the clear water scarcity challenges, a vast number of buildings are still being designed without crucial rainwater harvesting and greywater recycling infrastructure. Without water reuse methods like these and the necessary dual pipework, the scale of the challenge to protect water resources increases as water reuse can be highly complex to retrofit at a later date. A recent report highlighted retrofit costs added an additional 50% to the overall cost of the treatment system due to the need for a dual pipework supply (Source: Ricardo).

The time to make rainwater harvesting and greywater recycling systems mandatory in all new buildings is NOW, and here are some reasons why.

Unlocking enough water for future expansion of the built environment

Water Scarcity

The next five years are going to be critical if we are to avoid the predicted deficit in 2050. Much of England is already classed as “seriously water stressed” by the Environment Agency. Areas like Cambridge and West Sussex are already feeling the impacts of water scarcity which is preventing the expansion of the built environment in the local region.

Below are two examples of how much water could be unlocked by relying on rainwater harvesting in both commercial and communal residential settings…

Communal Rainwater Harvesting – Water Saving Potential

· Installing rainwater harvesting can save 25 litres per person per day (Source: Water Ready Report).

· Let’s take a look at the development of 800 new homes.

· If each property has an average of 2.4 occupants, this will result in a saving of 48,000 litres per day across the 800 homes.

· If these 800 homes were specified to use 110 litres per person per day, this would unlock enough water for 436 new homes!

· Let’s scale this up, if 250,000 properties are constructed between now and 2050 with water reuse, this could help to reduce the national deficit by 325 megalitres per day.

Commercial Rainwater Harvesting – Water Saving Potential

· Installing rainwater harvesting on a non-residential property can save an average of 10m3 per day.

· If a new development with 12 new distribution facilities opens, this whole development could save 120m3 per day which is equivalent to 120,000 litres.

· Over a year, this would result in a saving of 43.8 million litres of water!

· Let’s scale this up, if 2,600 commercial properties were constructed each year between now and 2050 with water reuse, this could help save 650 megalitres per day.

When we combine the commercial and communal system savings, this could result in rainwater harvesting and greywater recycling meeting up to 20.5% of the UK’s national daily deficit by 2050 (Source: UK Water Reuse Association).

As well as improved water efficiency, there are many other benefits for rainwater and greywater recycling to become mandatory in the UK…

Valuing rainwater and greywater

Rainwater and greywater are currently treated like a waste product. Because of this, the vast majority of rainwater and greywater is sent straight to a combined sewer for treatment which can lead to the system overflowing during heavy rainfall. Handling this locally in the form of rainwater harvesting or greywater recycling is a form of sustainable urban drainage and allows these sources of water to be treated as a resource rather than waste.

For water utility companies, this is the best of both worlds because it allows the opportunity to reduce combined sewer overflows on a mass scale. In Wales, Schedule 3 of the Flood and Water Management Act means that all developments over 100m2 requires sustainable drainage. As a result, the area has a seen a noticeable increase in the number of rainwater harvesting systems.

Across the world, the story is the same…

International Examples of Mandatory Water Reuse

Belgium – In the Flanders region, the enactment of the “Blue Deal” has resulted in rainwater harvesting being mandatory for roof areas over 80m2 and must have a storage capacity of 7,500 litres as a minimum.
Australia – In South Australia, new homes must have a minimum storage capacity of 1,000 litres.

So, do you think it is time to make rainwater harvesting and greywater recycling mandatory in the UK?

The Proposed Way Forward

The UK Water Reuse Association has proposed a new plan, titled “Water Reuse Ready” to guide the government on how mandatory water reuse can be implemented in the UK.

Here is a summary of the plan…

· 2025 – Introduce an advisory group working through legislative barriers and proposing solutions.

· 2026 – Get plumbers and installers of rainwater and greywater systems ready by introducing a water reuse module to the “Water Safe” Qualification.

· 2027 – Introduce new aligned legislation.

· 2028 – Introduce mandatory water reuse in seriously stressed zones.

· 2030 – Introduce mandatory water reuse in all areas of the UK.

More Information

There is a lot to cover with regard to making water reuse mandatory in the UK, so please keep an eye out for our upcoming content.

In the meantime, Stormsaver is encouraging every building and property designer to ensure their latest projects have water reuse installed to ensure the building is not adding to the issue of water scarcity. You can find out more about how we can support you through the design process here. With extensive experience, unrivalled bespoke solutions, and UK-manufactured products, we are the natural choice for all water reuse requirements.

Alternatively, you can join the campaign for mandatory water reuse in the UK by sharing this blog post with your network!

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An update for communal rainwater harvesting