| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 4954 | (44.81%) | -114 | (-1.03%) |
| Guadiana | 9261 | 2802 | (30.26%) | -22 | (-0.24%) |
| Guadalquivir | 8113 | 2472 | (30.47%) | -25 | (-0.31%) |
| Ebro | 7919 | 4920 | (62.12%) | 18 | (0.23%) |
| Duero | 7507 | 4190 | (55.81%) | -145 | (-1.93%) |
| Miño-Sil | 3030 | 1577 | (52.05%) | -25 | (-0.83%) |
| Júcar | 2846 | 1333 | (46.84%) | -8 | (-0.28%) |
| Guadalete-Barbate | 1651 | 597 | (36.16%) | -5 | (-0.30%) |
| Med. Andaluza | 1174 | 498 | (42.42%) | -9 | (-0.77%) |
| Segura | 1140 | 428 | (37.54%) | 0 | (0.00%) |
| Galicia Costa | 684 | 394 | (57.60%) | -16 | (-2.34%) |
| Cataluña Interna | 677 | 568 | (83.90%) | -2 | (-0.30%) |
| Cantabrico Occidental | 518 | 340 | (65.64%) | 1 | (0.19%) |
| Tinto, Odiel y Piedras | 229 | 135 | (58.95%) | -2 | (-0.87%) |
| Cantabrico Oriental | 73 | 62 | (84.93%) | 8 | (10.96%) |
| Pais Vasco Interna | 21 | 16 | (76.19%) | 0 | (0.00%) |
