The combined effects of climate change and increased tourism are placing ever-increasing pressure on water supplies in the Mediterranean. Water supply in the Greek islands has always been problematic and residents have traditionally used cisterns to collect winter rainfall for use in the summer. On some small islands water has been shipped in by boat, but this is becoming increasingly expensive. A few have installed desalination units, which provide a quick solution to water shortages but are energy-hungry and require constant maintenance – which has led to some falling into disuse. However, modern pressures have led to a resurgence of interest in desalination, the island of Gavdos being a recent example.