Water as a basic human right must be guaranteed to everyone, at least at a minimum level, to cover drinking, sanitation and hygiene needs. Using a database for the Tunisian governorates, this paper aims to fulfil two main objectives. First, the amount of water needed to cover basic household requirements is investigated based on the Stone-Geary utility function. Second, the costs associated with the minimum consumption are then utilized to examine the affordability and equity of water tariff based on: (i) affordability indexes; and (ii) concentration curves and inequality measurement indexes. Empirical evidence suggests that, at the national level, the minimum consumption is estimated at 102 m3 per household per year. Regarding the affordability analysis, water services seem to be affordable in Tunisia, since the minimum water charges represent a very small proportion of household income. Results also reveal that the distribution of water charges is not proportional to the distribution of household income. Consequently, the small weight of the water charges on household income allows a margin to increase water prices, whilst the water authority also has to consider some intergovernorate disparities in any adjustment of water tariffs.