Recently launched technology is now enabling self-builders to make more use of their water supply without any form of rationing or disruption to their existing lifestyle. Designed for use in residential, commercial and municipal properties, this water saving solution enables the collection of waste-water – so called ‘greywater’ – from baths and showers, and in some cases sinks, to be recycled and used for flushing toilets.
Suitable for retrofit as well as new build, greywater reuse systems reduce the mains water needs of a house or building by up to 30% and are designed to be easy to install and use. A revised plumbing set-up takes all waste-water from baths and showers and redirects it through a filtration unit to be treated with a disinfectant. This treated water is collected in a tank and piped on, as required, to supply all the flushing water needs for multiple toilets in the building.
Once fitted, the water saving potential is compelling. Based on daily usage figures of 150 litres of water per person – figures from the UK organisation, Waterwise – a family of five will typically save around 80,000 litres of water each year, the equivalent of 1000 baths, 1600 loads of washing or 328,000 cups of tea. An optional feature of these systems ingeniously allows heat to be extracted from the building’s greywater, before it’s recycled, so it can be fed back into the central heating system. Fitting a heat exchanger to the greywater reuse link between the bath, shower and toilet flush recaptures the heat energy from the bathing water, feeding it back into the building’s hot water system reducing fuel bills as well as enabling a two-fold reduction in CO2 emissions.
As most buildings in the UK have only one water supply, we have, until now, had little option but to put up with the confused logic of using drinking water to flush our toilets. With increasing pressure on our water supply from droughts, greywater reuse technology has the potential to make a big contribution to reducing water demand across the UK.
The technology’s relevance and appeal stretches beyond those with an environmental conscience to self-builders who pay for metered water. In metered areas, end users benefit from significant annual savings on their water bills.
Making use of recycled greywater rather than high-quality drinking water, leads to a reduction in the carbon footprint of a home or project. It contributes to the project’s environmental sustainability and complies with specific planning conditions as well as key current standards, in particular the Code for Sustainable Homes (CSH). A system like this also looks to the future, where the code’s water efficiency targets are likely to be enshrined in building regulations for new build projects.
One of the industry leaders, Ideal Standard, has already made the link between greywater technology and improving water efficiency. The bathroom specialist has teamed up with Reaqua Systems and code assessors, Stroma, to offer a specific package of greywater and sanitary ware options for the end-user which – if fitted in combination – are guaranteed to achieve significant and quantifiable water efficiencies.
Prior to this development, water efficiencies have been a challenge to achieve. Until now, water rationing technology, such as low flow showers and low flush toilets, have barely been able to deliver water efficiency savings, meeting a mediocre code four target under the CSH. Consumer feedback has also queried the value of this technology with criticism highlighting disappointingly low flow rates from showers or, worse, blocked waste pipes. Research has shown that using low flush toilets may not provide sufficient movement in small pipes to carry away solids, leading to blockages and flooding, and additional evidence suggests that these devices may act as a false economy with users running low flow showers for longer in order to improve their experience.
Delivering the water savings needed to reduce daily household usage to 80 litres per person – the usage considered to represent significant household water efficiencies and a high CHS rating – can only be found with some form of recycling, where water is repurposed rather than restricted, and this is why greywater reuse provides such a compelling option for the self-builder.
Targets in reach
Compared with the process of rainwater harvesting, where available rainwater is used to augment the water supply to a building, greywater reuse provides more quantifiable and predictable savings as supply is not weather dependent. Greywater also has a consistent level of acidity and, unlike rainwater, it is always just above room temperature – avoiding both the formation of condensation on toilet cisterns and any cooling of the room.
In summary, greywater reuse offers the industry the chance to reach ambitious and valuable code targets for water efficiency, without relying on the end user to make unpopular adjustments to their lifestyle. Bathing luxury with a conscience has arrived.