| Cuenca | Capacidad | Embalsada | Variación | ||
| Tajo | 11056 | 7822 | (70.75%) | -221 | (-2.00%) |
| Guadiana | 9538 | 5841 | (61.23%) | -81 | (-0.85%) |
| Guadalquivir | 8028 | 3826 | (47.66%) | -90 | (-1.12%) |
| Ebro | 7802 | 5013 | (64.25%) | -262 | (-3.36%) |
| Duero | 7602 | 5300 | (69.71%) | -234 | (-3.08%) |
| Miño-Sil | 3030 | 2315 | (76.40%) | -47 | (-1.55%) |
| Júcar | 2846 | 1530 | (53.76%) | -32 | (-1.12%) |
| Guadalete-Barbate | 1651 | 756 | (45.79%) | -14 | (-0.85%) |
| Med. Andaluza | 1174 | 590 | (50.26%) | -7 | (-0.60%) |
| Segura | 1140 | 291 | (25.53%) | -22 | (-1.93%) |
| Galicia Costa | 684 | 358 | (52.34%) | -24 | (-3.51%) |
| Cataluña Interna | 677 | 504 | (74.45%) | -10 | (-1.48%) |
| Cantábrico Occidental | 490 | 338 | (68.98%) | -8 | (-1.63%) |
| Tinto, Odiel y Piedras | 229 | 178 | (77.73%) | -2 | (-0.87%) |
| Cantábrico Oriental | 73 | 54 | (73.97%) | -1 | (-1.37%) |
| País Vasco Interna | 21 | 18 | (85.71%) | 0 | (0.00%) |
