| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11012 | 5137 | (46.65%) | -91 | (-0.83%) |
| Guadiana | 9261 | 4213 | (45.49%) | -80 | (-0.86%) |
| Guadalquivir | 8118 | 3651 | (44.97%) | -91 | (-1.12%) |
| Ebro | 7642 | 5518 | (72.21%) | -129 | (-1.69%) |
| Duero | 7507 | 4458 | (59.38%) | -105 | (-1.40%) |
| Júcar | 3337 | 1254 | (37.58%) | 4 | (0.12%) |
| Miño-Sil | 3030 | 2262 | (74.65%) | -36 | (-1.19%) |
| Guadalete-Barbate | 1651 | 917 | (55.54%) | 13 | (0.79%) |
| Med. Andaluza | 1174 | 692 | (58.94%) | -13 | (-1.11%) |
| Segura | 1140 | 309 | (27.11%) | -9 | (-0.79%) |
| Galicia Costa | 684 | 576 | (84.21%) | -17 | (-2.49%) |
| Cataluña Interna | 677 | 517 | (76.37%) | -14 | (-2.07%) |
| Cantabrico Occidental | 518 | 427 | (82.43%) | 8 | (1.54%) |
| Tinto, Odiel y Piedras | 229 | 171 | (74.67%) | -3 | (-1.31%) |
| Cantabrico Oriental | 73 | 62 | (84.93%) | -1 | (-1.37%) |
| Pais Vasco Interna | 21 | 17 | (80.95%) | 0 | (0.00%) |
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