| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 5486 | (49.62%) | -38 | (-0.34%) |
| Guadiana | 9261 | 2923 | (31.56%) | 10 | (0.11%) |
| Guadalquivir | 8113 | 2482 | (30.59%) | -2 | (-0.02%) |
| Ebro | 7919 | 5052 | (63.79%) | -14 | (-0.18%) |
| Duero | 7507 | 4476 | (59.62%) | -15 | (-0.20%) |
| Miño-Sil | 3030 | 1585 | (52.31%) | -19 | (-0.63%) |
| Júcar | 2846 | 1365 | (47.96%) | 11 | (0.39%) |
| Guadalete-Barbate | 1651 | 591 | (35.80%) | -2 | (-0.12%) |
| Med. Andaluza | 1174 | 478 | (40.72%) | -7 | (-0.60%) |
| Segura | 1140 | 392 | (34.39%) | -4 | (-0.35%) |
| Galicia Costa | 684 | 428 | (62.57%) | -12 | (-1.75%) |
| Cataluña Interna | 677 | 571 | (84.34%) | -2 | (-0.30%) |
| Cantabrico Occidental | 518 | 341 | (65.83%) | -3 | (-0.58%) |
| Tinto, Odiel y Piedras | 229 | 160 | (69.87%) | -1 | (-0.44%) |
| Cantabrico Oriental | 73 | 59 | (80.82%) | -1 | (-1.37%) |
| Pais Vasco Interna | 21 | 16 | (76.19%) | 0 | (0.00%) |
