| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 7462 | (67.49%) | -207 | (-1.87%) |
| Guadiana | 9261 | 3822 | (41.27%) | -6 | (-0.06%) |
| Guadalquivir | 8113 | 3382 | (41.69%) | -7 | (-0.09%) |
| Ebro | 7919 | 6184 | (78.09%) | -31 | (-0.39%) |
| Duero | 7507 | 5937 | (79.08%) | -94 | (-1.25%) |
| Miño-Sil | 3030 | 2271 | (74.95%) | -92 | (-3.04%) |
| Júcar | 2846 | 1740 | (61.14%) | 8 | (0.28%) |
| Guadalete-Barbate | 1651 | 766 | (46.40%) | -6 | (-0.36%) |
| Med. Andaluza | 1174 | 608 | (51.79%) | 4 | (0.34%) |
| Segura | 1140 | 511 | (44.82%) | 14 | (1.23%) |
| Galicia Costa | 684 | 513 | (75.00%) | -12 | (-1.75%) |
| Cataluña Interna | 677 | 589 | (87.00%) | -2 | (-0.30%) |
| Cantabrico Occidental | 518 | 403 | (77.80%) | -2 | (-0.39%) |
| Tinto, Odiel y Piedras | 229 | 188 | (82.10%) | 1 | (0.44%) |
| Cantabrico Oriental | 73 | 62 | (84.93%) | -1 | (-1.37%) |
| Pais Vasco Interna | 21 | 20 | (95.24%) | 0 | (0.00%) |
