A water treatment plant that would increase the overall production of Palta waterworks, which supplies potable water to more than half of Calcutta, will be thrown open on Thursday.

The new plant would produce 20 million gallon water every day. The additional production would benefit the water-scarce pockets in north, central and a small portion of south Calcutta.

The new plant was built after an old one became defunct and had to be dismantled, a senior engineer of the Calcutta Municipal Corporation said.

Once the plant starts operation on Thursday, Palta waterworks would produce up to 262 million gallon water in a day.

There are several water treatment plants spread across the 480-acre Palta waterworks, the engineer said.

Palta waterworks was built between 1864 and 1870, according to the corporation website. It started with a capacity of six million gallons per day (MGD) and was subsequently increased in phases as the city’s population grew and the demand for potable water increased.

The water generated at Palta is sent to the Tallah tank and from there it is distributed across north and central Calcutta. Water from Palta reaches up to Bhowanipore in south Calcutta, engineers said.

“Almost every ward has some lane or bylane where the water flow can improve. This happens because the farther an area, lesser is the pressure of water in the pipes,” the engineer said.

The additional 20 MGD water to be generated by the new plant would increase the pressure of water in the farthest areas, aiding better flow from taps, the engineer said.

The new plant was built under the corporation’s Kolkata Environmental Improvement Investment Programme funded by the Asian Development Bank. Work began in 2017 and the cost stood at Rs 46.92 crore.

The 262 MGD potable water to be produced at Palta after Thursday would be more than the combined potable water production in all other water treatment plants of the corporation.

The total water generated by the other plants —Dhapa, Watgunge, Jorabagan and Garden Reach — is 228 MGD, said a civic engineer.

A 25 MGD plant is being built at Garden Reach to increase capacity.

A tender will also be floated for increasing the capacity of Dhapa water treatment plant by another 20 million gallon a day.

There are plans to build a 10 MGD plant at Briji in Garia to end water crisis in pockets of Jadavpur and Tollygunge.