Traditionally this involves harvesting the rain from a roof.
Cistern no gutters.
This is a cistern i made from some pressure treated 2x6 material and a 55 gallon plastic juice drum.
It is more important that you have unrestricted flow into the cistern.
Screwed connections are stronger.
Install standard size mesh gutter covers over the entire gutter that will lead into the cistern.
Remember that the x section of a 4 pipe is twice that of a 3 pipe.
Cistern covers are 2 x2 and are cast in the floor.
Another method calls for gutters to be held in place by straps fastened to the roof.
Sweep all debris from the roof and gutters leading to the chosen downspout by using a broom.
This technique is usually only used when there s no fascia board.
Put them where they need to be.
Half round gutters rest in brackets screwed to the fascia.
If you join too many downspouts before they enter the cistern you could have a constriction that would be problematic.
The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel.
I chose to use 2x6 material because i had it handy but if you choose to u.
K style gutters can be spiked or screwed to the fascia.
The cistern typically located underground may be constructed of various materials including cinderblock reinforced concrete or precast concrete fiberglass or steel.