Anyone here know much about cisterns? About all I have is a general impression that people now consider them dangerous (?) and those who have old ones try to fill them in.

It's pouring down rain today here where I live, and I'm looking at the house across the way shooting umpteen gallons a minute out the end of the downspout - which runs off down the gutter, then storm drain. I'm thinking, what a waste.

We've had a couple of summers of drought in a row here, and what we could have done with all that water then. It just seems to me that for those with the room for one, that saved water could be very useful for watering the garden, washing clothes, flushing toilets and - with purification - drinking and cooking, when there might be a need.

Is there an overflow drain on those things so the water can run off and be refreshed? Or do they end up nasty and omeba-infested,like some neglected swimming pools I've seen?