Mark,
You should try to get that started in the UK as well, as you'l have around 50+ million toilets over there, so imagine how much water you'd save in that case
As for building using sea water, it already goes on, and for that reason alone, I wouldn't buy a house near the coast, anywhere in Cyprus
We had a water sump in the PSD when I worked at Akrotiri, which contained 50,000 ltrs of water incase of a fire. When we had the 6.5 earthquake in Aug 99, we had to check all the metal fuel tanks for leaks but found none, until we checked the concrete water sump, which had a crack in it, if it hadn't had a fibreglass lining, all 50,000 ltrs of water would have crashed out & straight into the office where me & the other lads where sitting during the quake
Once we found the crack, we got the royal engineers out to inspect it & they pulled away all the loose concrete to find the metal strengthening inside had corroded due to it being built with concrete made with sea water
So if you have a seaside property or intend buying one close to the sea, get the structure checked out