| Cuenca | Capacidad | Embalsada | Variación | ||
| Tajo | 11056 | 9407 | (85.09%) | -52 | (-0.47%) |
| Guadiana | 9538 | 6616 | (69.36%) | -57 | (-0.60%) |
| Guadalquivir | 8028 | 4718 | (58.77%) | -73 | (-0.91%) |
| Ebro | 7802 | 6999 | (89.70%) | 90 | (1.15%) |
| Duero | 7602 | 6975 | (91.75%) | -32 | (-0.42%) |
| Miño-Sil | 3030 | 2642 | (87.19%) | -31 | (-1.02%) |
| Júcar | 2846 | 1782 | (62.61%) | -14 | (-0.49%) |
| Guadalete-Barbate | 1651 | 881 | (53.36%) | -8 | (-0.48%) |
| Med. Andaluza | 1174 | 670 | (57.07%) | -5 | (-0.43%) |
| Segura | 1140 | 356 | (31.23%) | -2 | (-0.18%) |
| Galicia Costa | 684 | 504 | (73.68%) | -14 | (-2.05%) |
| Cataluña Interna | 677 | 560 | (82.72%) | 6 | (0.89%) |
| Cantábrico Occidental | 490 | 444 | (90.61%) | -7 | (-1.43%) |
| Tinto, Odiel y Piedras | 229 | 202 | (88.21%) | -2 | (-0.87%) |
| Cantábrico Oriental | 73 | 62 | (84.93%) | -1 | (-1.37%) |
| País Vasco Interna | 21 | 20 | (95.24%) | -1 | (-4.76%) |
