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 Tamil Nadu
74%Semi-critical
Groundwater is under pressure 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. Down 7 points since 2017.
15.0 billion m³pumped out each year (2025)
20.5 billion m³can be taken out safely each year
Noneno yearly shortfall
Extraction since 2009
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 |
|---|---|---|---|---|---|
| 2009 | 80.0% | 16.6 billion m³ | 20.6 billion m³ | Semi-critical | First assessment in this series. |
| 2017 | 80.9% | 14.7 billion m³ | 18.2 billion m³ | Semi-critical | Pumping down 11% (16.6 → 14.7 billion m³). Safe limit down 12% (20.6 → 18.2 billion m³). CGWB changed its method in 2017 (GEC-97 to GEC-2015), so part of this change comes from the new method. |
| 2020 | 82.9% | 14.7 billion m³ | 17.7 billion m³ | Semi-critical | Pumping down 0% (14.7 → 14.7 billion m³). Safe limit down 3% (18.2 → 17.7 billion m³). |
| 2022 | 75.6% | 14.4 billion m³ | 19.1 billion m³ | Semi-critical | Pumping down 2% (14.7 → 14.4 billion m³). Safe limit up 8% (17.7 → 19.1 billion m³). Main reason: more water soaked back into the ground, from better rain, canals or recharge structures. |
| 2023 | 73.9% | 14.4 billion m³ | 19.5 billion m³ | Semi-critical | Pumping down 0% (14.4 → 14.4 billion m³). Safe limit up 2% (19.1 → 19.5 billion m³). |
| 2024 | 74.3% | 14.4 billion m³ | 19.5 billion m³ | Semi-critical | Pumping up 0% (14.4 → 14.4 billion m³). Safe limit down 0% (19.5 → 19.5 billion m³). |
| 2025 | 73.5% | 15.0 billion m³ | 20.5 billion m³ | Semi-critical | Pumping up 4% (14.4 → 15.0 billion m³). Safe limit up 5% (19.5 → 20.5 billion m³). |
Million m³: 1 million m³ = 100 crore litres. 2009 and 2013 used the older GEC-97 method.
Loading 20 years of rainfall…
Ponds and lakes in Tamil Nadu
50,197 of 1,06,957 water bodies (47%) are not in use: dried up, silted, built over or polluted. Bringing them back is one of the cheapest ways to recharge groundwater.
1,06,957ponds, tanks, lakes and other water bodies
38,321of them are ponds (36%)
53%still in use (56,760)
8,366encroached upon
- Ponds38,321
- Tanks43,837
- Lakes13,629
- Reservoirs111
- Check dams and percolation tanks2,782
- Others8,277
Source: 1st Census of Water Bodies, Ministry of Jal Shakti (counted in 2018-19, published 2023).
All about the ponds and lakes in Tamil Nadu, district by district
What will fix it here
Most of the water here goes to homes and industry, so rooftop recharge and reuse make the biggest difference.
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 Tamil Nadu?
In the 2025 Central Ground Water Board assessment, Tamil Nadu pumped out 74% of the groundwater that can be safely taken out each year, which puts it in the "semi-critical" category. That is 7 points lower than in 2017.
Is groundwater in Tamil Nadu over-exploited?
No. At 74% of the safe yield, Tamil Nadu is semi-critical, though recharge is still needed as demand grows.
How can groundwater be recharged in Tamil Nadu?
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 Tamil Nadu?
The first Census of Water Bodies counted 1,06,957 water bodies in Tamil Nadu, including 38,321 ponds. 50,197 of them were not in use.
Districts of Tamil Nadu
Stage of extraction in 2025, most over-pumped first.
- 1Salem148%
- 2Tirupathur143%
- 3Vellore122%
- 4Chennai122%
- 5Dindigul117%
- 6Mayiladuthurai117%
- 7Namakkal116%
- 8Perambalur106%
- 9Karur103%
- 10Thanjavur101%
- 11Krishnagiri92%
- 12Coimbatore92%
- 13Dharmapuri90%
- 14Tiruvannamalai86%
- 15Tiruppur86%
- 16Villupuram85%
- 17Tiruchirappalli85%
- 18Ranipet85%
- 19Theni84%
- 20Kallakurichchi81%
- 21Erode77%
- 22Tenkasi76%
- 23Madurai70%
- 24Virudhunagar64%
- 25Chengalpattu64%
- 26Cuddalore63%
- 27Tiruvallur55%
- 28Thiruvarur54%
- 29Pudukkottai49%
- 30Kancheepuram49%
- 31Ariyalur48%
- 32Tirunelveli41%
- 33Thoothukudi28%
- 34Sivagangai26%
- 35Kanniyakumari14%
- 36The Nilgiris13%
- 37Ramanathapuram11%
- 38Nagapattinam0.0%