The water is free for anyone who needs a drink during a deadly heat wave that's killed more than 1,424 people in the past few days.
Most of the deaths -- 1,020 -- have been in the southeastern state of Andhra Pradesh, though another 340 have died in nearby Telangana, where Hyderabad is the capital.
People stop by Bai's stall every two minutes as the temperature slowly rises toward its peak, typically in mid- to late afternoon.
On Wednesday, temperatures in Hyderabad were forecast to hit a high of almost 43 degrees Celsius, or around 110 degrees Fahrenheit. Nights, while cooler, hover around a sticky 30 C or 86 F. During the day, humidity is around 30%.
Ice cream seller Bharat says evenings and early mornings are the best for business. He's selling twice as much ice cream compared with last year. But afternoons are typically quiet. It's too hot for most people to come onto the streets.
And that's where the true cost of this heat wave has been felt.
The poor and ill affected most
Millions of people in India are homeless. The streets are where they live with only rudimentary shelter. Air conditioning or even fans are a distant dream.
Many of those who have succumbed to the heat -- by dehydration or otherwise -- were too poor, frail or ill to cope.
However, the chief secretary of Telangana said many of the deaths in that state could have been avoided if victims had taken "a little more care."
Asked to explain his comments, B.R. Meena said: "Cover properly, have light color clothes, take umbrella, take care, be in cool area -- had they taken such care, this could have been avoided."
He said people were being urged to use an umbrella, hat or turban and drink plenty of water and avoid going outside between 11 a.m. and 4 p.m.
India recorded its highest maximum temperature of 47.6 C -- 117 F -- at Titlagarh in Odisha on Monday, according to the country's main weather office.
In many places in the country's north, central and eastern plains, temperatures are about two to five degrees higher than average.
Westerly winds blowing in from Pakistan's Sindh province was making already hot conditions worse, said B.P. Yadav, director of the India Meteorological Department.
Relief is expected to come in the form of monsoon rains later in the week, though the country's weather agency said another hot spell was likely to follow.