| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 5233 | (47.33%) | -125 | (-1.13%) |
| Guadiana | 9261 | 2903 | (31.35%) | -39 | (-0.42%) |
| Guadalquivir | 8113 | 2637 | (32.50%) | -57 | (-0.70%) |
| Ebro | 7642 | 4892 | (64.01%) | -164 | (-2.15%) |
| Duero | 7507 | 4753 | (63.31%) | -127 | (-1.69%) |
| Miño-Sil | 3030 | 1879 | (62.01%) | -105 | (-3.47%) |
| Júcar | 2846 | 1386 | (48.70%) | -26 | (-0.91%) |
| Guadalete-Barbate | 1651 | 634 | (38.40%) | -9 | (-0.55%) |
| Med. Andaluza | 1174 | 542 | (46.17%) | -9 | (-0.77%) |
| Segura | 1140 | 475 | (41.67%) | -12 | (-1.05%) |
| Galicia Costa | 684 | 399 | (58.33%) | -11 | (-1.61%) |
| Cataluña Interna | 677 | 579 | (85.52%) | -10 | (-1.48%) |
| Cantabrico Occidental | 518 | 370 | (71.43%) | -11 | (-2.12%) |
| Tinto, Odiel y Piedras | 229 | 144 | (62.88%) | -2 | (-0.87%) |
| Cantabrico Oriental | 73 | 51 | (69.86%) | -1 | (-1.37%) |
| Pais Vasco Interna | 21 | 15 | (71.43%) | 0 | (0.00%) |
