What is rainwater harvesting?
Capturing rain where it falls — usually from a rooftop — and storing it or guiding it into the ground, instead of letting it flow away into drains.
Live rainfall · NASA POWER
Where does
rainwater go?
Discover how much rainwater your rooftop could potentially harvest — and see what that water could do for your home and community.
20+ yrs
of rainfall records
3 steps
to your estimate
Free
public & educational
How it works
Four steps to your rain report
01 · Locate
Enter your location
Type your city or let your browser detect it — we find the rainfall pattern for your exact coordinates.
02 · Measure
Enter your rooftop area
The surface that catches the rain, in square feet. We convert it to square metres for you.
03 · Analyse
We analyse the rainfall
Long-term monthly rainfall records from NASA POWER are matched to your rooftop, month by month.
04 · Discover
See your potential
Litres you could store, recharge into the ground, and what that water could do for your household.
Field notes
Why every drop deserves a plan
Why does rooftop harvesting matter?
A roof is a ready-made catchment. Even a modest rooftop can collect tens of thousands of litres a year, easing pressure on wells, tankers and municipal supply.
How does groundwater recharge work?
Surplus water is directed into recharge pits, trenches or shafts. It percolates through the soil and refills the aquifers that wells and borewells draw from.
Why is local rainfall important?
Rainfall varies enormously from place to place and month to month. Your own location's pattern decides whether your roof is a reservoir or a spillway.
Why manage rain instead of letting it run off?
Unmanaged runoff floods streets, erodes soil and carries pollution into rivers — while the groundwater below runs dry. Every litre captured is used twice: once by you, once by the earth.
About ADI
Turning water knowledge
into community action
Alternative Development Initiatives (ADI) works with communities on water resource management, climate resilience and sustainable livelihoods — translating rainfall data into decisions people can own.