Rainwater Harvesting Explained

Build for rain

It rained all last summer and it s been raining all this winter. Yet the reservoirs are not full, the rivers which provide over 70 percent of our mains water are running dry. But in 2006 it was the driest summer on record with hosepipe bans and parched gardens everywhere. In Great Britain we have been spoilt by access to cheap and plentiful water. This is changing. Many water companies are planning desalination plants to meet increased demand and 10 companies in August proposed price rises that could lead to a 40 percent increase in water bills within 5 years.

The credit crunch hitting the building industry is having repercussions everywhere; all the more reason to give a building project added value by installing a rainwater harvesting system. Investment in a rainwater harvesting system can increase the value of a new or renovated home by many times the cost of the equipment. And in comparison to the overall cost, a rainwater system need not be expensive. The current price for a typical home system for outdoor use, for WCs and washing machines with a 3750 litre underground tank, accessories and top of the range mains back up is around pounds sterling 2500 including VAT and delivery. A 3600 litre above ground system for outdoor use costs just over pounds sterling 1000. Do this and you could save up to 50% on mains water consumption and relieve flood threats.

The Pressure is on 
as demand for water grows, at long last we are officially encouraged to use rainwater instead of mains water whenever possible:

1. As of 1 May 2008, the mandatory rating against the Code for Sustainable Homes puts pressure on to install rainwater harvesting in new builds.

2. Planning applications with rainwater harvesting are favored. (Planning Policy Statement, Climate Change, December 2007)

3. Businesses can benefit from the Enhanced Capital Allowance scheme to benefit from a tax rebate. 

4. New legislation will give water boards greater powers during water shortages. Hosepipes will be banned for topping up pools, hot tubs and decorative ponds, as well as for watering gardens and outdoor cleaning. DEFRA can impose even more severe drought restrictions at any time. 

Flood Avoidance

Last summer and this summer have seen bad floods. In some areas, the tendency to flooding has been encouraged by the increased use of hard-standing round houses, particularly when additional off road parking is needed. Some councils are already encouraging the use of permeable surfaces, rainwater tanks and perforated drainpipes to absorb excess water in downpours. In this case, rainwater harvesting serves a double function of providing free water and offsetting potential flood damage.

It's common sense

With a little extra investment, rainwater can be used inside to feed WCs and washing machines. Installing a domestic system is more straightforward in a new-build home, but with some alterations to down-pipes and interior plumbing, a system can be added to existing houses. Water tanks of 2000 to 7000 litres are needed for feeding the home and we can supply you with the accessories needed, including pumps, super filters and a mains switchover panel which transfer the rainwater supply system to the mains if the tank runs out. 

A typical kit includes:

integrated filter, 
telescopic lid and turret, 
overflow siphon and rodent barrier, 
calmed inlet, 
floating pump intake

Mains backup options (if you've got toilets and washing machine connected you need to have an automatic switch over to mains water when the rain runs out)

a) submersible pump with remote floating switch

b) rain manager with pump and mains switch in one unit 

c) the new Rain Director which ensures a constant head of clear rainwater for washing machines, toilets, the garden and other uses. An intelligent header tank in the home is controlled by electronic level sensors, valves and control panel in a user-controllable unit. This ensures fail-safe mains backup with smart header tank, saves energy and prolongs pump life, avoids brackishness in header tank, Assures water supply during a power cut, automatic and user-controlled functions, and handy controls but no pump noise.

Why pay for water when its available off your own roof?