An improved water source (or improved drinking-water source or improved water supply) is a term used to categorize certain types or levels of water supply for monitoring purposes. It is defined as a type of water source that, by nature of its construction or through active intervention, is likely to be protected from outside contamination, in particular from contamination with fecal matter.[1]
The term was coined by the Joint Monitoring Program (JMP) for Water Supply and Sanitation of UNICEF and WHO in 2002 to help monitor the progress towards Goal Number 7 of the Millennium Development Goals (MDGs). The opposite of "improved water source" has been termed "unimproved water source" in the JMP definitions.
The same terms are used to monitor progress towards Sustainable Development Goal 6 (Target 6.1, Indicator 6.1.1) from 2015 onwards.[2] Here, they are a component of the definition for "safely managed drinking water service".