In Cities : If you live in a single dwelling house or a multi-tenant apartment complex, you already have 80% of the RWH system. We just need re-orient the plumbing design.The present design of the house will take all the rainwater from the roof and all the ground level areas surrounding the house and flow the water towards the street. (where it floods the street,clogs the storm drains and sewer lines for a few days, before flowingaway as sewage water) .From the roof tops, bring the rainwter down using closed PVC pipes and direct it to a sump. Include a simple 3-part filteration unit consisting of sand, brick jelly and broken mud bricksIf you do not have sump, use a well. In many parts of the country, old wells when they go dry, is used as garbage dumps. Please clean the well and put the rain water into it.
If you do not have a well, construct a baby well (about 2ft in diameter and about 16 feet deep based on soil structure)
Other types of RWH - collect the ground water and stop their flow at the gate. Put a concrete slab with holes in it, build a 2 feet deep pit, across the full width of the gate. Collect and connect a pipe and flow the water to a well or a baby well.
If there are existing water tanks in the village, desilt and dredge them every 3 years. If there are any small rivers or streams, build check-dams across them to hold the rain water for usage after the rains have stopped.