| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11012 | 4121 | (37.42%) | -211 | (-1.92%) |
| Guadiana | 9261 | 3732 | (40.30%) | 0 | (0.00%) |
| Guadalquivir | 8118 | 2928 | (36.07%) | -59 | (-0.73%) |
| Ebro | 7642 | 3951 | (51.70%) | -173 | (-2.26%) |
| Duero | 7507 | 3433 | (45.73%) | -121 | (-1.61%) |
| Júcar | 3337 | 991 | (29.70%) | -20 | (-0.60%) |
| Miño-Sil | 3030 | 2041 | (67.36%) | -25 | (-0.83%) |
| Guadalete-Barbate | 1651 | 798 | (48.33%) | -12 | (-0.73%) |
| Med. Andaluza | 1174 | 614 | (52.30%) | -6 | (-0.51%) |
| Segura | 1140 | 240 | (21.05%) | -5 | (-0.44%) |
| Galicia Costa | 684 | 486 | (71.05%) | -11 | (-1.61%) |
| Cataluña Interna | 677 | 411 | (60.71%) | -10 | (-1.48%) |
| Cantabrico Occidental | 518 | 363 | (70.08%) | -10 | (-1.93%) |
| Tinto, Odiel y Piedras | 229 | 147 | (64.19%) | 0 | (0.00%) |
| Cantabrico Oriental | 73 | 54 | (73.97%) | -2 | (-2.74%) |
| Pais Vasco Interna | 21 | 15 | (71.43%) | -1 | (-4.76%) |
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