| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 4857 | (43.93%) | -29 | (-0.26%) |
| Guadiana | 9498 | 2855 | (30.06%) | -4 | (-0.04%) |
| Guadalquivir | 8113 | 2136 | (26.33%) | -2 | (-0.02%) |
| Ebro | 7919 | 3855 | (48.68%) | -6 | (-0.08%) |
| Duero | 7507 | 2990 | (39.83%) | -54 | (-0.72%) |
| Miño-Sil | 3030 | 1218 | (40.20%) | -47 | (-1.55%) |
| Júcar | 2846 | 1471 | (51.69%) | 3 | (0.11%) |
| Guadalete-Barbate | 1651 | 486 | (29.44%) | -3 | (-0.18%) |
| Med. Andaluza | 1174 | 395 | (33.65%) | -5 | (-0.43%) |
| Segura | 1140 | 378 | (33.16%) | -4 | (-0.35%) |
| Galicia Costa | 684 | 346 | (50.58%) | -12 | (-1.75%) |
| Cataluña Interna | 677 | 431 | (63.66%) | -5 | (-0.74%) |
| Cantabrico Occidental | 518 | 297 | (57.34%) | -12 | (-2.32%) |
| Tinto, Odiel y Piedras | 229 | 149 | (65.07%) | 1 | (0.44%) |
| Cantabrico Oriental | 73 | 51 | (69.86%) | 0 | (0.00%) |
| Pais Vasco Interna | 21 | 14 | (66.67%) | 0 | (0.00%) |
