About two billion people worldwide lack basic sanitation services. Most of them are living in remote and rural communities, depending on agriculture for their livelihoods. Therefore, the priorities of water consumption in these communities are drinking and irrigation. In these areas, the required infrastructure for common sanitation practices including flushing toilets and advanced wastewater treatment is not applicable. The Resource Circulation Sanitation System is a nature-based solution for providing sustainable sanitation in such areas. The source-separated urine and feces undergo an onsite-controlled nitrification treatment that recycles them as fertilizer. Water for sanitation is provided through a rainwater harvesting system, and the produced greywater can be treated onsite for irrigation. The system meets the WHO guidelines and does not require complex infrastructure. Its contribution to sustainability has been approved through successful showcase projects in South Korea.