I'm embarking on a building project which consists of several structures approximately 10m x 10m, I am thinking that a 10m x 10m x 1m concrete sump under the structure would provide a lot (100,000 liters) of needed rainwater storage during the cool season but I have no idea if this would be a; cost effective or b; advisable to do? Additionally what would be required in terms of treatment (settling tanks, filtration and/or chlorination) to make the water safe for showering, washing up etc.

I am also looking at similar. I am thinking of  maybe 5m x5m x2m reinforced concrete walls with concrete planks and concrete on top to hie. This would catch rainwater and also water from well, which would inturn feed 2 ponds.

Not looking to use for showers though.

Google cistern water systems. These were pretty popular in California’s early days.

I would read up on them before I did anything.

Mosquitos might be an issue.

1 hour ago, mogandave said:

Google cistern water systems. These were pretty popular in California’s early days.

I would read up on them before I did anything.

Mosquitos might be an issue.

If finished with a sealed lid, which it will, and a pump house on top, also with some chlorine or bleach added, no mossies.

Is this talking about a concrete cavity under the slab for purpose of storing water?  That just can't be a good idea, can it?  

31 minutes ago, bankruatsteve said:

Is this talking about a concrete cavity under the slab for purpose of storing water?  That just can't be a good idea, can it?  

Why not ? many places do it, better than hug tank above ground? This is only to irrigate land.

32 minutes ago, oldwelshman said:

Why not ? many places do it, better than hug tank above ground? This is only to irrigate land.

The Romans loved the idea and built a few under public areas.

 

1 hour ago, Fruit Trader said:

The Romans loved the idea and built a few under public areas.

The Romans had a surplus of "slaves" they could send in to clean the tanks, hopefully without complaining!