Rooftop rainwater recharge
Pipe roof water through a silt trap and filter into a recharge pit or an old borewell. Every 100 m² of roof puts back tens of thousands of litres a year, right where the pumping happens.
Groundwater use is within safe limits here. That is the 2024 stage of groundwater extraction: water pumped out in a year as a share of what rain and other sources safely put back. Down 12 points since 2017.
Each point is one CGWB assessment. Over-exploited means more water leaves the ground than comes back, so the water table keeps falling. Hover over or tap a point to see why it moved.
| Year | Stage | Pumped out | Safe limit | Category | What changed |
|---|---|---|---|---|---|
| 2009 | 74.0% | – | – | Semi-critical | First assessment in this series. |
| 2013 | 66.0% | – | – | Safe | Down 8 points since 2009. |
| 2017 | 64.7% | 0.4 million m³ | 0.6 million m³ | Safe | CGWB changed its method in 2017 (GEC-97 to GEC-2015), so part of this change comes from the new method. |
| 2020 | 56.5% | 0.5 million m³ | 0.9 million m³ | Safe | Pumping up 25% (0 → 1 million m³). Safe limit up 50% (1 → 1 million m³). Main reason: more water soaked back into the ground, from better rain, canals or recharge structures. A swing this large usually comes partly from revised estimates (a new well count or changed district boundaries), not only from changes on the ground. |
| 2022 | 52.9% | – | – | Safe | Down 4 points since 2020. |
| 2024 | 53.0% | 0.9 million m³ | 1.6 million m³ | Safe | Little change since 2022 (+0.1 points). |
Million m³: 1 million m³ = 100 crore litres. 2009 and 2013 used the older GEC-97 method.
Loading 20 years of rainfall…
Groundwater here is in balance. Keeping it that way means recharging as the area builds up and paves over.
Pipe roof water through a silt trap and filter into a recharge pit or an old borewell. Every 100 m² of roof puts back tens of thousands of litres a year, right where the pumping happens.
Treated water from a sewage treatment plant can run flushing, gardens, cooling towers and construction, which today often draw on borewells.
Parks, campuses, warehouse yards and road sides can take recharge shafts that reach past the clay layer, so runoff that floods streets goes down to the aquifer instead.
Metered and registered borewells, leak repairs in supply lines and water-efficient fixtures cut pumping without anyone going short.
Desilting old ponds and opening their feeder channels restores natural recharge. A one-hectare pond that soaks in a metre of water over the monsoon puts back about a crore litres.
Porous pavers, unpaved tree pits and bioswales along roads let rain soak in instead of racing to the drain.
In the 2024 Central Ground Water Board assessment, Androth (Lakshadweep) pumped out 53% of the groundwater that can be safely taken out each year, which puts it in the "safe" category. That is 12 points lower than in 2017.
No. At 53% of the safe yield, Androth is safe, though recharge is still needed as demand grows.
Rooftop rainwater harvesting into recharge pits or old borewells, recharge shafts in open land, reviving ponds, check dams, treating and reusing wastewater, and moving farms to drip irrigation and less thirsty crops.
Yearly rain at Androth, 2006–2025, from NASA satellite data. Lighter bars are dry years (20% or more below average), when wells are drawn hardest.