On 15 May 2014, Bob Eager grunted:
Yeah, we have two here; one of them used to feed the outside bog (which was accessed from outside but built into the house; we did away with it and incorporated the space into the house when we had an extension built.
As we only had old narrow-bore supply pipes the plumber working on the job recommended rather than capping it off, incorporating this second supply into the house, which is what happened; with the slightly bizarre result that we have two entirely separate rising mains and stopcocks both of which need turning off to shut off the incoming water.
The even more odd part is that there's a water company stopcock out in street, which IIRC only shuts off one of our incoming supplies. No idea where the second supply comes from. We get our water unmetered, but it could make life interesting if we ever decide to go metered, wouldn't it? :)