Remember that the x section of a 4 pipe is twice that of a 3 pipe.
Cistern no gutters.
If you join too many downspouts before they enter the cistern you could have a constriction that would be problematic.
Put them where they need to be.
Install standard size mesh gutter covers over the entire gutter that will lead into the cistern.
I chose to use 2x6 material because i had it handy but if you choose to u.
The water might have been used by the household if there was no city water at the time.
The water was collected from the roof gutters.
Traditionally this involves harvesting the rain from a roof.
I got the used drum locally for 15 and the wood came from my scrap bin.
The cistern typically located underground may be constructed of various materials including cinderblock reinforced concrete or precast concrete fiberglass or steel.
A system of gutters and downspouts directs the rainwater collected by the roof to the storage cistern.
Sweep all debris from the roof and gutters leading to the chosen downspout by using a broom.
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.
A cistern is an underground tank for storing water.