| Cuenca | Capacidad | Embalsada | Variación | ||
| Tajo | 11056 | 6226 | (56.31%) | -76 | (-0.69%) |
| Guadiana | 9538 | 3759 | (39.41%) | -22 | (-0.23%) |
| Guadalquivir | 8028 | 2418 | (30.12%) | -49 | (-0.61%) |
| Ebro | 7802 | 4575 | (58.63%) | 138 | (1.77%) |
| Duero | 7600 | 4737 | (62.33%) | -25 | (-0.33%) |
| Miño-Sil | 3030 | 1946 | (64.22%) | -31 | (-1.02%) |
| Júcar | 2846 | 1165 | (40.93%) | -10 | (-0.35%) |
| Guadalete-Barbate | 1651 | 342 | (20.71%) | -7 | (-0.42%) |
| Med. Andaluza | 1174 | 270 | (23.00%) | -4 | (-0.34%) |
| Segura | 1140 | 184 | (16.14%) | -6 | (-0.53%) |
| Galicia Costa | 684 | 365 | (53.36%) | 11 | (1.61%) |
| Cataluña Interna | 677 | 195 | (28.80%) | -3 | (-0.44%) |
| Cantábrico Occidental | 490 | 347 | (70.82%) | 2 | (0.41%) |
| Tinto, Odiel y Piedras | 229 | 164 | (71.62%) | -1 | (-0.44%) |
| Cantábrico Oriental | 73 | 61 | (83.56%) | 1 | (1.37%) |
| País Vasco Interna | 21 | 19 | (90.48%) | 0 | (0.00%) |
