| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11012 | 6019 | (54.66%) | -19 | (-0.17%) |
| Guadiana | 9261 | 4809 | (51.93%) | -67 | (-0.72%) |
| Guadalquivir | 8118 | 4360 | (53.71%) | -82 | (-1.01%) |
| Ebro | 7642 | 5957 | (77.95%) | 62 | (0.81%) |
| Duero | 7507 | 4970 | (66.20%) | 13 | (0.17%) |
| Júcar | 3337 | 1388 | (41.59%) | -13 | (-0.39%) |
| Miño-Sil | 3030 | 2338 | (77.16%) | 24 | (0.79%) |
| Guadalete-Barbate | 1651 | 1036 | (62.75%) | -14 | (-0.85%) |
| Med. Andaluza | 1174 | 762 | (64.91%) | -5 | (-0.43%) |
| Segura | 1140 | 370 | (32.46%) | -8 | (-0.70%) |
| Galicia Costa | 684 | 624 | (91.23%) | 11 | (1.61%) |
| Cataluña Interna | 677 | 583 | (86.12%) | -4 | (-0.59%) |
| Cantabrico Occidental | 518 | 461 | (89.00%) | 1 | (0.19%) |
| Tinto, Odiel y Piedras | 229 | 183 | (79.91%) | -2 | (-0.87%) |
| Cantabrico Oriental | 73 | 65 | (89.04%) | 4 | (5.48%) |
| Pais Vasco Interna | 21 | 19 | (90.48%) | 0 | (0.00%) |
|