Electrification can reduce the dependence on combustible fuels and therefore also reduce the concomitant health risks. Hydro power is one possible method of generating electric power close to the potential consumers, thereby cutting out expensive reticulation costs in widely spread rural areas. For sustainable electricity generation there must be stream flows of sufficient flow rates down significant slopes. A preliminary assessment of hydro power potential in South Africa was undertaken by estimating actual energy potential calculated from digital maps of slope and runoff. Coefficients of variation and low flow indices proved good potential measures of flow variability and risk. The methodology allowed rapid identification of micro- and macro-hydro power potential. Micro-hydro power potential identification was calculated from run of river and local flow, while macro-hydro power generation needs storage and thus cumulative river flows were used. The steeper and more humid slopes of the eastern escarpment, and parts of the southern escarpment near Cape Town, showed the best potential for both micro- and macro-hydro power (with annual energy potential values in excess of 107 kWh yr−1 and 109 kWh yr−1, respectively). This preliminary assessment was intended to lead to further more detailed and in-field assessments of hydro power generating capacity.