The UK is one of the only countries in Europe that flushes their toilets with drinking water. The drinking water supply is expensive to produce and uses valuable energy. The water companies meter the water used by the householder in many towns, and this can be expensive. The rainwater that falls onto the roof is often collected in a water butt and used for garden irrigation, but the capacity of this butt is usually quite small and overflows to the drain. The idea of this project is to bury a large tank in the garden of the property and plumb in a pumped water supply from the tank to feed water to toilet flush, outside taps and can even be used for the laundry. This will save the house owner money with a short term payback of the capital costs. It also has a 'green' impact by lowering the carbon footprint caused by producing the wasted drinking water. There is also a possible larger scale of rainwater harvesting installation on a new build development which would have a tank and pumping installation to feed all the houses on the estate.
The funds are to be used to advertise the concept and try to get more people on side by having trial equipment installed with a lower install cost using funds raised.
This incentive should be from the government, and it was going to be some years ago. But the water supply companies (mainly French owned) complained about the potential loss to revenue and forced a stop to the funding.