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 level in Kolkatta
0.0%Safe
Groundwater use is within safe limits here. That is the 2025 stage of groundwater extraction: water pumped out in a year as a share of what rain and other sources safely put back. Up 0 points since 2023.
Extraction since 2023
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.
Safe · up to 70%Semi-critical · 70–90%Critical · 90–100%Over-exploited · above 100%
Show the numbers
| Year | Stage | Pumped out | Safe limit | Category | What changed |
|---|---|---|---|---|---|
| 2023 | 0.0% | – | – | Safe | First assessment in this series. |
| 2024 | 0.0% | – | – | Safe | Little change since 2023 (+0.0 points). |
| 2025 | 0.0% | – | – | Safe | Little change since 2024 (+0.0 points). |
Million m³: 1 million m³ = 100 crore litres. 2009 and 2013 used the older GEC-97 method.
Rainfall, last 20 years
Rainfall data is unavailable right now, so estimates on this page assume 700 mm a year.
Ponds and lakes in Kolkatta
906 of 3,051 water bodies (30%) are not in use: dried up, silted, built over or polluted. Bringing them back is one of the cheapest ways to recharge groundwater.
Loading the map of water bodies in Kolkatta…
- Ponds2,718
- Tanks301
- Lakes32
Source: 1st Census of Water Bodies, Ministry of Jal Shakti (counted in 2018-19, published 2023).
What will fix it here
Groundwater here is in balance. Keeping it that way means recharging as the area builds up and paves over.
Recharge pits and shafts in open land
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.
Revive village ponds and johads
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.
Treat and reuse wastewater
Treated water from a sewage treatment plant can run flushing, gardens, cooling towers and construction, which today often draw on borewells.
Check dams and contour trenches
On sloping or rocky land, small dams on seasonal streams and trenches along contours slow water down long enough for it to sink in.
Meter borewells and fix leaks
Metered and registered borewells, leak repairs in supply lines and water-efficient fixtures cut pumping without anyone going short.
Frequently asked questions
What is the groundwater level in Kolkatta?
In the 2025 Central Ground Water Board assessment, Kolkatta (West Bengal) pumped out 0% of the groundwater that can be safely taken out each year, which puts it in the "safe" category. That is 0 points higher than in 2023.
Is groundwater in Kolkatta over-exploited?
No. At 0% of the safe yield, Kolkatta is safe, though recharge is still needed as demand grows.
How can groundwater be recharged in Kolkatta?
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.
How many ponds and lakes are there in Kolkatta?
The first Census of Water Bodies counted 3,051 water bodies in Kolkatta, including 2,718 ponds. 906 of them were not in use.