Tanzania, as many other countries, has designed an ambitious Rural Water Supply and Sanitation Plan (RWSSP) to improve increase access to rural water: from 53% in 2005, up to 74% in 2015 and 90% in 2025. Emphasis is placed on the production of new schemes and only 6% of investment is foreseen for rehabilitation. This paper presents an analysis of the current functionality-time relationship for water points found in en extensive water point mapping study made in three regions of Tanzania, covering 15% of the total rural population of the country. Results show very low performance over time, since only between 35% and 47% of water points are working 15 years after installation. Consequences for the accomplishment of the RWSSP are discussed and some measures proposed.