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 Kollam
47%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. Down 2 points since 2017.
153 million m³pumped out each year (2025)
323 million m³can be taken out safely each year
Noneno yearly shortfall
33%goes to irrigation; the rest to homes and industry
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 | 38.0% | 157 million m³ | 409 million m³ | Safe | First assessment in this series. |
| 2013 | 45.0% | 163 million m³ | 365 million m³ | Safe | Pumping up 4% (157 → 163 million m³). Safe limit down 11% (409 → 365 million m³). Main reason: less water soaked back in, from weaker rain, less canal seepage or more paved ground. |
| 2017 | 49.5% | 165 million m³ | 333 million m³ | Safe | Pumping up 1% (163 → 165 million m³). Safe limit down 9% (365 → 333 million m³). Main reason: less water soaked back in, from weaker rain, less canal seepage or more paved ground. CGWB changed its method in 2017 (GEC-97 to GEC-2015), so part of this change comes from the new method. |
| 2020 | 48.6% | 165 million m³ | 340 million m³ | Safe | Pumping up 0% (165 → 165 million m³). Safe limit up 2% (333 → 340 million m³). |
| 2022 | 49.9% | 169 million m³ | 338 million m³ | Safe | Pumping up 2% (165 → 169 million m³). Safe limit down 1% (340 → 338 million m³). |
| 2023 | 51.9% | 168 million m³ | 323 million m³ | Safe | Pumping down 0% (169 → 168 million m³). Safe limit down 4% (338 → 323 million m³). |
| 2024 | 50.2% | 170 million m³ | 338 million m³ | Safe | Pumping up 1% (168 → 170 million m³). Safe limit up 5% (323 → 338 million m³). |
| 2025 | 47.3% | 153 million m³ | 323 million m³ | Safe | Pumping down 10% (170 → 153 million m³). Safe limit down 4% (338 → 323 million 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 Kollam
508 of 2,352 water bodies (22%) 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 Kollam…
- Ponds2,278
- Tanks37
- Lakes1
- Reservoirs1
- Check dams and percolation tanks15
- Others20
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.
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.
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.
Meter borewells and fix leaks
Metered and registered borewells, leak repairs in supply lines and water-efficient fixtures cut pumping without anyone going short.
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.
Permeable paving and green cover
Porous pavers, unpaved tree pits and bioswales along roads let rain soak in instead of racing to the drain.
Frequently asked questions
What is the groundwater level in Kollam?
In the 2025 Central Ground Water Board assessment, Kollam (Kerala) pumped out 47% of the groundwater that can be safely taken out each year, which puts it in the "safe" category. That is 2 points lower than in 2017.
Is groundwater in Kollam over-exploited?
No. At 47% of the safe yield, Kollam is safe, though recharge is still needed as demand grows.
How can groundwater be recharged in Kollam?
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 Kollam?
The first Census of Water Bodies counted 2,352 water bodies in Kollam, including 2,278 ponds. 508 of them were not in use.