How to plan rainwater harvesting for an independent house: recharge pits, storage, costs and maintenance — and why it's often required for building permission.
Groundwater levels in many parts of Hyderabad and other cities have fallen sharply. Rainwater harvesting (RWH) puts water back into the ground — and many municipalities require it for building permission.
Two ways to harvest
- Recharge — roof water is filtered and sent into a recharge pit or well, refilling the groundwater that feeds your borewell.
- Storage — water is collected in a tank or sump for use in gardening, washing or, after treatment, other purposes.
A typical recharge pit
- Located away from the foundation and the septic tank.
- Filled with layers of boulders, gravel and coarse sand that filter the water.
- Connected to roof down-pipes, with a first-flush arrangement to discard the dirtiest first rain.
Planning tips
- Plan RWH at the design stage — it's cheaper than retrofitting.
- Keep roof and terrace slopes leading to the down-pipes.
- Size the pit according to roof area and local rainfall.
- Don't connect toilet or kitchen waste water.
Maintenance
Clean the filter and the top layer of sand before every monsoon, and check pipes for blockages.
RWH is a small investment that keeps your borewell alive for years. We include a recharge pit in our house designs wherever the plot allows.
