| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 4482 | (40.54%) | -105 | (-0.95%) |
| Guadiana | 9498 | 2448 | (25.77%) | -42 | (-0.44%) |
| Guadalquivir | 8113 | 1942 | (23.94%) | -63 | (-0.78%) |
| Ebro | 7919 | 4078 | (51.49%) | -257 | (-3.25%) |
| Duero | 7507 | 3170 | (42.23%) | -108 | (-1.44%) |
| Miño-Sil | 3030 | 1529 | (50.46%) | -21 | (-0.69%) |
| Júcar | 2846 | 1662 | (58.40%) | -36 | (-1.26%) |
| Guadalete-Barbate | 1651 | 448 | (27.14%) | -15 | (-0.91%) |
| Med. Andaluza | 1174 | 524 | (44.63%) | -10 | (-0.85%) |
| Segura | 1140 | 455 | (39.91%) | -5 | (-0.44%) |
| Galicia Costa | 684 | 424 | (61.99%) | -10 | (-1.46%) |
| Cataluña Interna | 677 | 285 | (42.10%) | -12 | (-1.77%) |
| Cantabrico Occidental | 518 | 320 | (61.78%) | -5 | (-0.97%) |
| Tinto, Odiel y Piedras | 229 | 159 | (69.43%) | -3 | (-1.31%) |
| Cantabrico Oriental | 73 | 53 | (72.60%) | -1 | (-1.37%) |
| Pais Vasco Interna | 21 | 17 | (80.95%) | 0 | (0.00%) |
