Chembarambakkam, the biggest of Chennai’s drinking water reservoirs, was at about 35% of capacity on 14 October as the northeast monsoon arrived. City lakes were drying fast before the rains, Deccan Chronicle reported, leaving Chennai dependent on a good monsoon. How fast it fills over the next ten weeks will shape the city’s water supply well into 2027.
The city’s smaller lakes tell a different story: they have shrunk, taken in sewage and lost their links to one another. That loss is one reason colonies around them flood every few years. Here is where the main lakes stand and what the state and courts are doing about them.
The big reservoirs
Chembarambakkam, Puzhal (Red Hills), Poondi and Cholavaram are the reservoirs managed by the Water Resources Department (WRD) that feed Chennai Metrowater. Chembarambakkam is also a flood control structure: when it nears full level, WRD releases surplus water into the Adyar river, and residents downstream along the river are warned before releases.
- Follow WRD and district administration alerts before and during heavy rain.
- Releases are announced in advance; residents in low-lying areas along the Adyar should move valuables and vehicles to higher ground when a big release is announced.
- The state has also sought extra Krishna water from Andhra Pradesh this season, and a ₹3,108 crore Ring Main System is planned to link the reservoirs to distribution stations.
Porur and Velachery: two different fates
Porur lake, on the south-western edge of the city, is one of the few lakes inside the urban area that still supplies drinking water, and it is linked to the Chembarambakkam system. That role has given it some protection: a lake that feeds a treatment plant is watched more closely than one that does not. Restoration has come at a cost too. Families who had settled on the lake’s edges have been moved to resettlement colonies on the city’s fringe, a pattern repeated at several Chennai waterbodies.
Velachery lake shows the other path. Over decades, large parts of its bed and catchment were built on, including land allotted by government agencies for housing. What remains is a fraction of the original waterbody, and it receives sewage from surrounding streets. The neighbourhood’s repeated flooding is partly a result: water that once spread across the lake now has nowhere to go but into homes and roads. Restoration plans for the lake have proposed fencing, walkways and the removal of encroachments, but residents say sewage inflow has to stop first.
For residents near either lake, the practical point is the same. Waterbody land shown as such in revenue records cannot be lawfully built on, and properties on former lake beds carry a flood risk that no title deed removes.
Madipakkam, Pallikaranai and the southern chain
South Chennai’s lakes, including those at Madipakkam, Velachery, Keelkattalai and Medavakkam, were once part of a chain that drained into Pallikaranai marsh. The state’s Ramsar information sheet says about 54 smaller waterbodies spill their surplus into the marsh in the monsoon. Roads and buildings have broken many of those links.
Madipakkam is one of the 11 revenue villages covered by CMDA’s September 2025 freeze on planning permission within about a kilometre of the marsh, ordered after National Green Tribunal proceedings, Citizen Matters reported. In its report to the tribunal, CMDA said its Master Plan marks the swamp and other sensitive areas as ecologically sensitive, and that it was waiting for confirmed survey numbers from the wetland authority to fix the boundaries on its maps.
What is being done now
The revised 2026-27 State Budget promised blue-green infrastructure around waterbodies: raising retaining walls, adding fencing and improving discharge capacity, Deccan Chronicle reported. CMDA is also preparing a Third Master Plan for 2027 to 2046, which will decide how waterbodies and their surroundings are zoned.
What residents can do:
- Before buying land near a lake, check the survey number in revenue records and with CMDA. Waterbody poramboke land cannot legally be built on.
- Report dumping, filling or construction on a lake bed to the Corporation (1913) and WRD.
- Report sewage entering a lake to Metrowater.
- Join or form a lake group with your residents’ welfare association; several Chennai lakes are monitored this way.
Property questions involve legal risk, so consult a lawyer before you buy.
Quick answers
How full is Chembarambakkam lake?
About 35% of capacity on 14 October 2026. Levels change daily during the monsoon.
Who manages Chennai’s lakes?
WRD manages the big reservoirs and many system tanks. The Corporation looks after some smaller urban lakes.
Why does Velachery flood?
Much of the area is built on what was once lake bed, and the marsh it drained into has also shrunk.
Can I build near Madipakkam lake?
Madipakkam falls under CMDA’s Pallikaranai 1-km planning freeze. Check with CMDA first.
Information checked against official sources on 18 October 2026. Fees, dates and rules can change; confirm on the linked official pages before acting.
Sources
- O.A. 91 of 2023 (SZ), Additional Status Report by CMDA (National Green Tribunal)
- Ramsar Information Sheet: Pallikaranai Marsh Reserve Forest (Tamil Nadu State Wetland Authority)
- Pallikaranai’s 1-km buffer zone sparks debate (Citizen Matters, Feb 2026)
- Cooum, Adyar restoration back on agenda: TN budget 2026-27 (Deccan Chronicle, 6 Aug 2026)
- Chennai looks to NE monsoon as lakes drying up fast (Deccan Chronicle)
