Andy Thompson, National Sales Manager – Plumbing & Heating at Wilo UK, discusses the key advantages of rainwater harvesting systems in new build housing developments.
It’s understandable to think that water shortages equal a lack of rainfall. Yet, with the UK having experienced the wettest 18 months on record, this can’t be further from the truth. With flooding on the rise, alongside a growing demand for water supply, this leaves a predicted deficit of almost five billion litres of water a day by 2050, more than a third of water currently put into public supply.
As a result, regional newbuild housing developers face the unenviable task of reducing reliance on potable water supply, all while incorporating services that help to differentiate them from competitors. Rainwater harvesting systems might just be the solution to both.
What are the key benefits to developers?
When it comes to newbuild developments, it’s becoming more common to see planning permission only given to those that have considered ways of reducing stress upon local water supplies, storm surges and overflows. Rainwater harvesting systems do just that, preventing flooding downstream while capturing rainwater for reuse in toilet flushing, washing machines and garden irrigation, for instance.
Hose pipe bans are already in place during hot and dry periods, with people prohibited from using them to wash their cars and water their gardens. Enter rainwater harvesting systems to help keep plants looking at their finest for as long as possible. An average house can capture around 70,000 litres of rainwater per year, depending on its geographical location, so why not use softer water, that is ideal for plant growth and nutrient absorption, to keep the hydrangeas alive?
Rainwater harvesting systems also create the potential for newbuilds to make significant savings for eventual tenants, especially the growing number that are being fitted with water meters. With the average person using around 150 litres of water per day, rainwater can be collected to reduce the proportion that is supplied by the mains to flush toilets, wash clothes, watering the garden – the list is goes on. What’s more, ‘soft’ rainwater helps to reduce limescale, meaning that fewer cleaning products and less detergent is required, presenting the chance for further savings.
What should developers consider?
The National Building Regulations and Water Supply Regulations 1999 state that rainwater harvesting systems must use an airgap to stop backflow and avoid the risk of contaminating the water supply. Most European systems, however, do not feature an airgap and are therefore not approved for UK use. Developers are encouraged to check that their chosen system is approved prior to the point of purchase.
Another key consideration is the size of the accompanying storage tank. Be it underground or above ground, a general rule of thumb is that tanks should be able to hold a maximum of 18 days’ worth of water. Storage tends to range from 3,000 to 9,000 litres for a domestic property, so developers should consider what the rainwater harvesting system in question will be used for and, as a result, how much water storage is actually needed. Storage tanks should contain a leaf and debris filter, or a filter installed upstream of the tank in a position with easy access for periodic cleaning. It’s generally accepted that filters must be cleaned at least once a month to avoid overflow or a build-up of moss and other debris.
Part G of the Building Regulations 2010 also stipulates a maximum allowance of 125 litres of wholesome water per person per day in dwellings, despite the average usage still sitting at 150 litres. To add more of a challenge, a potential condition of planning permission in newbuilds that can be implemented is that water consumption should not exceed 110 litres per person per day, meaning that around 25% of water must be sourced from elsewhere; this stipulation can be made where water supply could be under stress in the local area. When deciding between rainwater harvesting systems for newbuild properties, developers should consider a storage tank sizeable enough to help account for this.
While rainfall patterns are used to calculate the yield from a roof area, most areas within the UK will provide sufficient rainfall to effectively utilise a system. Consideration, however, must be given to the collection surface, as this will determine the level of water that can be accumulated, alongside intended uses for the rainwater, number of occupants within the property and the material of the building’s roof.
What solutions are available?
The latest systems make rainwater reuse a simple task. The Wilo-RAIN1, for instance, offers easy installation thanks to its ready-to-plug system and compact design with various hydraulic connection options. Ease of use goes the extra mile with a unique combination of an intuitive LCD touch screen and a variety of control functions that help to facilitate a convenient operation.
The latest systems make rainwater reuse a simple task. The Wilo-RAIN1, for instance, offers easy installation thanks to its ready-to-plug system and compact design with various hydraulic connection options. Ease of use goes the extra mile with a unique combination of an intuitive LCD touch screen and a variety of control functions that help to facilitate a convenient operation.
Are rainwater harvesting systems become a necessity?
Newbuild developers have a crucial role to play when it comes to increasing both the awareness and uptake of rainwater harvesting systems. With water companies planning to increase household bills to pay for structure upgrades, alongside the prediction that several regions in England will run out of water by 2030, it’s imperative that any method of saving water is explored and acted on.
Within the coming years rainwater harvesting systems are going to become a necessity rather than option, and Wilo is on hand to guide developers throughout the process of specifying solutions for new build housing.
For more information on the Wilo-RAIN1 visit https://wilo.com/gb/en/
