Rainwater Harvesting for Irrigation
One monsoon can fill enough rainwater to irrigate your terrace garden for 8 months. Here's the system: tank, first-flush, drip — under Rs 8,000.
Size the tank
Formula: roof area (m2) x annual rainfall (mm) x 0.8 = litres collectable. A 100 m2 Bengaluru roof yields ~70,000 L/year. A 1,000 L tank is the sweet spot for terrace gardens.
First-flush diverter
First 2 mm of rain washes dust and bird droppings. A simple PVC diverter (Rs 400) sends that to drain and clean water to your tank.
Connect to drip
Place the tank 1 metre above bed level for gravity-fed drip. Or add a Rs 1,200 booster pump for full-pressure irrigation.
Keep it clean
Mosquito mesh on the inlet, lid on the tank, and a quick clean before each monsoon. Test pH yearly — most rainwater sits at 6.5, perfect for veggies.
📌 Next steps: Try the Autonomy Simulator or browse crop guides.