We've put guttering on the new roof and it now feeds into a raised water tank which will gravity feed into the kitchen. The rains finally came a few days ago and it filled up within 24 hours, so we rigged up the overflow to go into the black tank, which filled up the following day. During the summer we have long dry spells and will have to pump the water from the over-flow back up to the green tank. We're not sure yet how many overflow tanks we'll need to get us through the dry season, but we'll find out next summer.
This water is used for washing only, not drinking. There is a font in the village where we collect our drinking water.