Water supply and sanitation in Tanzania has been characterised by decreasing access to improved water sources in the 2000s (especially in urban areas), steady access to some form of sanitation (around 93 per cent since the 1990s), intermittent water supplies, and generally low quality of service. Many utilities are barely able to cover their operation and maintenance costs through revenues because of low tariffs and poor efficiency. There are significant regional differences, with the best performing utilities being Arusha, Moshi, and Tanga.