Reining in the rising cost of water was a big theme at last week’s Agricultural Buildings Show in Shepton Mallet, Somerset.

As both mains and extracted water get dearer, recycling your rainwater is becoming increasingly attractive. And equipment suppliers are gearing up to provide the hardware to make this possible.

Endon, Staffordshire, firm Receau started offering German-made systems for capturing and storing rainwater in 2006 and now has 13 set-ups around the UK. These involve taking rainwater from shed roofs, putting it through a filter and storing it in one or more tanks.

If the water is simply for washing down yards, a straightforward mesh filter will take out leaves and twigs. The water is then be stored in an above-ground (typically 9cu m) polyethylene tank.

If the water is for cattle drinking purposes, it will need to pass through a pre-filter, then a UV filter. Above-ground tanks can still be used to store it, but there needs to be enough flow to prevent bacteria and algae building up. Otherwise, a more expensive below-ground tank is needed.

Water is becoming an increasingly expensive commodity, especially for stock farmers, says the firm’s Barry Jackson. The average dairy farm uses 100 litres a cow for drinking water, 30 litres a day for the milk cooler and 25 litres a day for washing. For a 200-cow herd, that is 11,300cu m of water used in a year.

Parlour washing

Mains water costs between 80p and £1.40/cu m, so that means an annual water bill between £9040 and £15,820. Water companies are predicted to push up water costs up by about 7% a year between now and 2015, so expect those figures to rise sharply.

Mr Jackson says a standard set-up for rainwater recycling costs between £10,000 and £12,000. With a typical shed roof area of about 4860sq m and annual rainfall of 1100mm, that should yield about 4800cu m of water, thereby knocking 40% (or between £3840 and £6720) off the annual water bill. At that rate, payback should be 2-2.5 years at current water prices.

Rainwater recycling kit (if it’s on the approved equipment list) also attracts the new Enhanced Capital Allowances (www.eca-water.gov.uk), so you can set 100% of the cost against profits (if you are making any) in the first year.

Rainwater tank mankers like Titan Pollution Control also report rising demand from farmers for tanks for saving rainwater. But the firm’s JP Dorgan said some farmers still did not realise how much their water was costing. “Many people are still using mains water to wash down their collecting yards,” he said. “They could save money by using the rainwater falling on their roofs.”