The shocking photo, shared by Environmental Agency staff, shows a desolate Clywedog Reservoir, where water levels remain very low despite welcome rain.
The reservoir, near Llanidloes, regulates the flow of water in the River Severn and enables the supply of 50 million litres of drinking water to the West Midlands.
Readings from September 26 revealed water levels at the giant reservoir have fallen to 40.3 per cent capacity - a fall of 11.5 per cent in less than a month.
Last week the Environmental Agency warned that significant action was needed to manage water levels as most of England remains in drought.
The agency warned that many areas could still be in drought well into next year, as data revealed the country's reservoir stocks were at 52 per cent of total capacity as of September 20.
The dramatic photo of Clywedog paints a bleak reminder of the necessity of conserving water, even as winter draws nearer.
Severn Trent has already issued water-saving advice alongside a plea for customers to conserve water.
Last month, a spokesperson from Severn Trent said: "Throughout the year, our teams have worked hard to protect water supplies during the driest conditions in a century, and even though we’ve had some rain in the last few weeks, we’re asking people to continue to be mindful of water use, especially if there is a dry autumn and winter.
"We're continuing to see an increasing demand for water, at the same time as the region experiencing the driest summer months since 1850, with little rain in the forecast. We’d like to say a massive thank all our customers for continuing to use water wisely."