According to the SDG definition, safely managed drinking water services refer to water from an improved water source (e.g. piped water, boreholes or tube wells, protected dug wells, springs, rainwater, and packaged or delivered water) that is located on premises, available when needed and free from faecal and priority chemical contamination. Basic drinking water services in contrast refer to drinking water from an improved source, but with a collection time of not more than 30 minutes for a round trip, including queuing. Service delivery models range from self-supply and community managed to direct local government and utility managed, with different types of ownership (public, private, public-private). Key criteria for water supply include quantity, quality, reliability and accessibility.