… water for your new house …

About the author

Lutz Johnen is the MD of Aquality Trading & Consulting Ltd, and a founder-member and Chairman of the UK Rainwater Management Association.

water-supplies under stress …

DEFRA’s recently published progress report on the Government’s 25-Year Plan for the Environment, makes interesting reading for any enviro-conscious self-builder, not least where it relates to water.  Acknowledging existing stresses on water supplies, and the additional increased pressures likely to arise in coming years from population growth and climate-change, one of the key aims of the Government’s Plan is to ensure adequate future supplies of good-quality water for both people and the environment.

The growing challenge in this respect is illustrated by the graphic which shows the water-related difficulties already being faced by agriculture and, by implication, the natural environment.  It is therefore hardly surprising that the Plan aims to tackle the challenge in part, by aiming further to reduce domestic mains-water consumption below current Building Regulations requirements.

making better use of available water …

By far the most straightforward way of doing that would be to make rainwater harvesting systems as normal a feature of a new UK house, as is already the case on mainland Europe in countries experiencing similar water-supply stresses.

Rainwater harvesting systems are very straightforward to install in new-build homes; they operate simply by gathering roof water via standard guttering and downpipes, then filtering-out solid matter before storing it underground for later re-use.  The storage tanks are sized according to the roof area and occupancy of the property concerned, to provide around 20-days consumption in dry weather from full.  The stored water is then delivered through dedicated pipework to services which do not require potable water, typically the toilets, clothes-washing machine and garden tap.

Current Building Regulations require new homes to be designed and built so that they use no more mains-water than 125-litres per person per day, on average; generally, this can be achieved by a combination of water-efficient appliances, smaller baths and wash-hand basins/sinks, and water-efficient taps and shower-heads.

To reduce average daily consumption significantly below the current requirements will mean either having new homes without baths, or the substitution of harvested rainwater for some of the mains water that would otherwise be used.  Typically, this latter approach would reduce the mains-water consumption down to around 80-litres per person per day.  And, better still for keen gardeners, if designed-in from the outset, the system can also be a source of garden irrigation water – even when hose-pipe bans are enforced.

making better use of available water …

By far the most straightforward way of doing that would be to make rainwater harvesting systems as normal a feature of a new UK house, as is already the case on mainland Europe in countries experiencing similar water-supply stresses.

Rainwater harvesting systems are very straightforward to install in new-build homes; they operate simply by gathering roof water via standard guttering and downpipes, then filtering-out solid matter before storing it underground for later re-use.  The storage tanks are sized according to the roof area and occupancy of the property concerned, to provide around 20-days consumption in dry weather from full.  The stored water is then delivered through dedicated pipework to services which do not require potable water, typically the toilets, clothes-washing machine and garden tap.

Current Building Regulations require new homes to be designed and built so that they use no more mains-water than 125-litres per person per day, on average; generally, this can be achieved by a combination of water-efficient appliances, smaller baths and wash-hand basins/sinks, and water-efficient taps and shower-heads.

To reduce average daily consumption significantly below the current requirements will mean either having new homes without baths, or the substitution of harvested rainwater for some of the mains water that would otherwise be used.  Typically, this latter approach would reduce the mains-water consumption down to around 80-litres per person per day.  And, better still for keen gardeners, if designed-in from the outset, the system can also be a source of garden irrigation water – even when hose-pipe bans are enforced.