Fertilizer consumption per cubic meter of freshwater is taken as a proxy for global water quality indicator. A global model of environmental quality for 121 countries confirms the Kuznet's hypothesis. Global turning point is reached at nearly five times the average income of all countries. Foreign Direct Investment (FDI) was significant to increase the national income. Increased aid and larger farm size per capita favored higher environmental quality, albeit insignificant. A flow of better technology and possible non-agricultural employment might help improve water quality in developing countries when their net income increases.