| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 5488 | (49.64%) | -92 | (-0.83%) |
| Guadiana | 9498 | 3042 | (32.03%) | -28 | (-0.29%) |
| Guadalquivir | 8113 | 2612 | (32.20%) | -4 | (-0.05%) |
| Ebro | 7919 | 6100 | (77.02%) | 14 | (0.18%) |
| Duero | 7507 | 4319 | (57.53%) | -27 | (-0.36%) |
| Miño-Sil | 3030 | 1668 | (55.05%) | -7 | (-0.23%) |
| Júcar | 2846 | 1875 | (65.88%) | 5 | (0.18%) |
| Guadalete-Barbate | 1651 | 601 | (36.40%) | -8 | (-0.48%) |
| Med. Andaluza | 1174 | 603 | (51.36%) | 9 | (0.77%) |
| Segura | 1140 | 518 | (45.44%) | 4 | (0.35%) |
| Galicia Costa | 684 | 472 | (69.01%) | -7 | (-1.02%) |
| Cataluña Interna | 677 | 409 | (60.41%) | 4 | (0.59%) |
| Cantabrico Occidental | 518 | 321 | (61.97%) | -13 | (-2.51%) |
| Tinto, Odiel y Piedras | 229 | 184 | (80.35%) | 0 | (0.00%) |
| Cantabrico Oriental | 73 | 68 | (93.15%) | -1 | (-1.37%) |
| Pais Vasco Interna | 21 | 21 | (100.00%) | 0 | (0.00%) |
