Summer reach peak: Hyderabad’s twin reservoirs turn green
Water in Osman Sagar and Himayat Sagar has turned green, prompting concern among authorities. Officials attribute the change to monsoon vegetation and summer heat, while intensifying monitoring and testing to ensure safe drinking water supply across Hyderabad.
Published Date - 2 May 2026, 05:50 PM
Hyderabad: With summer temperatures peaking, the colour of water in the twin reservoirs of Osman Sagar and Himayath Sagar has been turning green over the past few weeks, causing concern for the Hyderabad Metropolitan Water Supply and Sewerage Board (HMWSSB).
The water board officials have been monitoring the situation and initiating measures to tackle the issue and ensure supply of clean and safe potable water.
The change in water colour has been going on since early April and one possibility being reasoned by the officials is the heavy inflows into these reservoirs during last monsoon. An official said the twin reservoirs experienced heavy floodwater, and tons of unwanted vegetation floated from upstream areas and accumulated at the floodgates. This vegetation accumulated during last monsoon could be causing the change in water colour, the official said.
Another possibility for the change in water colour in these reservoirs is the extreme heat conditions since the onset of this summer season. “The colour change is being noticed since summer season started to peak,” quipped an official.
HMWSSB Managing Director K Ashok Reddy deployed special teams to ensure pure and safe drinking water to around one lakh consumers who are provided water from here.
As part of measures initiated, water samples were being collected starting from the source and up to the doorstep of the consumer, a HMWSSB QAT Wing official told ‘Telangana Today’. “Around 3,000 water samples are collected every day and sent to our Quality Assurance & Testing (QAT) wing to check the quality,” the official said.
Twin reservoirs stand as a lifeline to several parts of the Old City, with residents depending on them for daily water needs. The reservoirs continue to play a key role in supplying water across multiple localities, particularly during periods of high demand.
Water from this source quenches the thirst of more than 70 per cent of the Old City and the remaining 30 per cent goes to some areas of Banjara Hills, Jubilee Hills, and Red Hills. For last several decades, treated water has been supplied from Asif Nagar filter beds, which were built in 1920. The raw water from Osman Sagar reservoir goes to Asif Nagar filter beds through a 14 km conduit by gravity for treatment.
Twin reservoirs at a glance:
| Reservoir |
Normal drawal |
Present drawal |
| Osman Sagar |
27 MGD |
26 MGD |
| Himayath Sagar |
18 MGD |
12 MGD |