Richard Wylde, a hydrologist at the Swedish Meteorological and Hydrological Institute, said that after more than a year of unusually dry weather, parts of Sweden could face water shortages even if the coming summer is wetter than usual.
"It's a relatively serious situation both for ground water and for surface waters," he said.
"If it were to rain from today with normal amounts of rainfall, we would still expect to see restricted access to water across large parts of Sweden."
Swedish Radio has identified several municipalities which have already brought in hosepipe bans and made plans for water deliveries, such as Södertälje and Nykvarn.
Wylde said that what has made the situation so critical is that low rainfall over the winter failed to replenish lakes and rivers depleted by the preceding dry summer.
"What makes this exceptional is that we've had a very long period now without normal rainfall," he said. "It's really the length of time that this has been ongoing for now that makes it a very serious situation."