Creating a global core set of indicatorsthat can be integrated into existing monitoring efforts orharnessed as a foundation for new monitoring efforts willimprove the efficiency of the sector and still enablecollection of locally-relevant information. Following aWorld Bank review of 40 different existing rural waterindicator frameworks from national and development partnerproject systems, a set of 24 existing indicators wasidentified as a potential set of global core metrics forrural water supply. This knowledge note describeschallenges, opportunities, implementation, and next stepsfor measuring what works in rural water.