Environmental sustainability is one among the eight United Nations Millennium Development Goals (MDGs) for Sustainable development. As a measure of this goal, proportion of people with sustainable access to improved water source is in indicator of progress towards its achievement by the year 2015. This study assessed the emerging scarcity of water and analyzed opportunities for improvement in six rural villages of the Usangu plain in south-western Tanzania. A combination of the literature survey, participatory rural appraisal, formal survey, participant observations and biophysical data collection were research tools used. A problem of water shortage for domestic use exists and is increasing in the Usangu plain. In the area of study, only 13% of the households had full time access to improved sources of water. This proportion is very low, compared to national average of 65.7% in 1999, and the national target to be achieved is 82.1% by year 2015. Environmental change, manifested by increasing drought events, decline of water levels in underground aquifers, streams, rivers and springs, and observed increased losses through runoff floods are the major causes of emerging shortages of the water, Use of techniques that increase conservation and infiltration of the rainwater in the watershed areas of the major sources would enhance the recharge of underground aquifers and reduce floods. Technologies and skills, that would enable local people to directly harvest rainwater and tap underground water and manage these sources effectively, at household or sub-village community levels, seem to be sustainable solutions to the scarcity of safe drinking water supply in this semi-arid environment, where there is increasing rainfall amount and pattern variability. (c) 2008 Elsevier Ltd. All rights reserved.