i'm looking into maybe buying a local round that uses wfp for tops and trad for bottoms,just wondered about how much water you use with wfp and costs involved when you pay for your water at home (water meter).Any advice would be appreciated.
Cheers
I rent a small place and my water usage (including waste) was about 34,000 litres for the first two months. This will drop as I put a restrictor on the waste after a couple of weeks. 34,000 litres @ about £1.70 per cubic metre is around £58. I am not particularly frugal with my usage as I prefer to work with a decent flow rate.
If you do tops only, maybe reckon on about 40-45% of usage as more glass is on ground floors.
Hi Paul, Whats a restrictor on the waste?
It's just a small plastic tap on the waste pipe of the RO. At the point I have fitted it, it is a John Guest 3/8" pipe. The tap is designed to receive the pipe on either side. I just cut the waste pipe and push fitted the tap in. Very tricky to set exactly though as even a tiny movement can make a big difference to the flow rate through the waste pipe. I've got it set about 60/40 pure/waste on a Merlin. It certainly ups the resin usage and possibly shortens the life of the membranes. However, the ratio before fitting the restrictor was about 1/4 pure/waste. I did my sums and the extra resin costs are far less than the higher water charge would have been. The unknown quantity is what it will do to the membranes. In about 10 weeks the output from the RO has gone from 22 to 28 TDS. Before I had a restrictor it was about 15 TDS.
The Merlin was fine when I was not on a meter as I could just let it run freely through the waste. Ultimately, I may choose to buy a different RO which is more efficient than a Merlin.