The water was collected from the roof gutters.
Cistern no gutters.
The water might have been used by the household if there was no city water at the time.
A cistern is an underground tank for storing water.
The cistern typically located underground may be constructed of various materials including cinderblock reinforced concrete or precast concrete fiberglass or steel.
I got the used drum locally for 15 and the wood came from my scrap bin.
Put them where they need to be.
Remember that the x section of a 4 pipe is twice that of a 3 pipe.
A system of gutters and downspouts directs the rainwater collected by the roof to the storage cistern.
This is a cistern i made from some pressure treated 2x6 material and a 55 gallon plastic juice drum.
The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel.
Rainwater harvesting is collecting the run off from a structure or other impervious surface in order to store it for later use.
It is more important that you have unrestricted flow into the cistern.
Sweep all debris from the roof and gutters leading to the chosen downspout by using a broom.
Cistern covers are 2 x2 and are cast in the floor.
Traditionally this involves harvesting the rain from a roof.