We have analysed all Swiss hydropower reservoirs with a capacity above 1 million m3: ‐ 63 reservoirs > 1 hm3 ‐ 40 reservoirs > 10 hm3 ‐ 29 reservoirs > 30 hm3 ‐ 36 reservoirs > 60 hm3 These 168 dams represent 8778 GWhof storage capacity, which is over 99% of the total Swiss hydropower storage capacity. The results show that a significant number of dams could increase storage in a significant way: ‐ 48 dams could capture existing excess natural inflows if their current storage capacity were to be increased. ‐ 7 dams are sub-optimally used, and could catch additional inflows using existing infrastructure.