| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11012 | 5774 | (52.43%) | 4 | (0.04%) |
| Guadiana | 9261 | 4999 | (53.98%) | -4 | (-0.04%) |
| Guadalquivir | 8118 | 4464 | (54.99%) | -18 | (-0.22%) |
| Ebro | 7642 | 5643 | (73.84%) | -74 | (-0.97%) |
| Duero | 7507 | 4720 | (62.87%) | 41 | (0.55%) |
| Júcar | 3337 | 1244 | (37.28%) | 0 | (0.00%) |
| Miño-Sil | 3030 | 2036 | (67.19%) | -30 | (-0.99%) |
| Guadalete-Barbate | 1651 | 1079 | (65.35%) | -4 | (-0.24%) |
| Med. Andaluza | 1174 | 783 | (66.70%) | -3 | (-0.26%) |
| Segura | 1140 | 332 | (29.12%) | 3 | (0.26%) |
| Galicia Costa | 684 | 510 | (74.56%) | -8 | (-1.17%) |
| Cataluña Interna | 677 | 587 | (86.71%) | -4 | (-0.59%) |
| Cantabrico Occidental | 518 | 408 | (78.76%) | 7 | (1.35%) |
| Tinto, Odiel y Piedras | 229 | 185 | (80.79%) | -1 | (-0.44%) |
| Cantabrico Oriental | 73 | 62 | (84.93%) | 0 | (0.00%) |
| Pais Vasco Interna | 21 | 19 | (90.48%) | 0 | (0.00%) |
