Grey water recycling and rain water harvesting

Green self building is all about not wasting the resources we have. And one of the most precious of these is water.

Water is essential for life and is becoming increasingly valuable globally. Even in this country, with its apparent abundance of rain water, we have been subjected to water meters and huge water bills.

Ideally we should be conserving water ie not wallowing in super deep baths. Not only will this cut down the water used, but also the energy required to heat it in the first place.

But we can also use water in a more green manner by recycling it, either by reusing grey water from baths and showers or collecting rain water, for such tasks as flushing toilets and irrigating gardens - and when you think of it, it is madness to be using drinking water for that anyway.

Greywater recycling

Grey water is the used water that comes from the showers, baths and sinks and is suitable for re-use as opposed to the black water (from toilets) which is not reused.

Greywater recycling systems collect this water, treat it and re-use it to flush toilets, water gardens and sometimes feed washing machines.

Treatment systems come under two main categories - physical and chemical systems. Physical systems (commonly used in small scale systems) use filtration to clean the water.

Chemical treatment is generally used in larger systems and works in a similar way to the processes used at a sewage treatment works. Some systems use a combination of the two methods.

Untreated grey water can be a breeding ground for bacteria, so should not be used as drinking water or to water edible plants.

Harvesting rain water

Rainwater harvesting is simply the process of collecting the rain which fall onto roofs, then storing it in a tank until needed.

Rain falls onto the roof, flows into the gutter and into the down pipe which leads to a rain butt or to a storage tank (usually underground).

Water destined for domestic use is filtered and then pumped, when required, to the point of use (or to a header tank). Rain water can be used for watering the garden, flushing toilets and for washing machines.

By collecting rain water, this amount of water is kept out of the drains, helping storm-water management and reducing the risk of local flooding.

Household rain water harvesting systems can be sophisticated and their installation is quite complex. They can be as comprehensive as to provide potable water. At the other end of the scale, they can be extremely simple - such as a down pipe feeding into a water barrel with hosepipe attached to the bottom for irrigating the garden.

Is a greywater recycling system suitable for you

If the amount of greywater you are likely to generate (which will depend on the number of baths / showers taken) is high a grey water system can save you money, particularly if you have a high demand for reclaimed water (toilet flushes / water required for the garden).

You will need to balance the savings made against the cost of installation and maintenance. Installing a system for use in an individual property can be expensive. A typical, off the shelf, single house, domestic system may cost in excess of £3,000 to purchase and then their are the running costs and installation costs on top of that.

Your financial savings will depend both on the price of water in your area and the volume of water re-used. Typically the larger your household, the more you'll benefit.

Once only of interest to a small minority, green is the new black as far as self-building is concerned.

With the effects of global warming becoming increasingly apparent, more and more people are seeking greener ways to provide the energy needed to run a home.

Whether it's solar panels, heat pumps, high specification glazing or eco-friendly wool insulation in the loft space, there is little doubt that it is self-builders who are setting the standards for a greener future for the building industry and the way we live our lives.

Underfloor heating for example, has been available for years but, by and large, the self build market has been the industry's bread and butter - with large scale property developers still opting for standard, less efficient radiators.

But it's not all about saving the planet. Incorporating green ideas into a home can lead to reduced running costs and save you money in the medium to long term too. And when you come to sell your home in the future, you can guarantee that the greener it is the more attractive it will be to prospective buyers.

There is a greater sense of purpose from the government to promote green alternatives too with a stick and carrot approach in place.

Building regulations now demand far better energy efficiency while government grants are available for loft insulation right through to solar panels, heat pumps, wind turbines and other microgeneration technologies.

Self-builders are leading the way as far as greener homes are concerned and greenselfbuild.co.uk will be with you every step of the way towards a greener future for you, your family and the wider community.