| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11012 | 5593 | (50.79%) | -125 | (-1.14%) |
| Guadiana | 9261 | 4964 | (53.60%) | 1 | (0.01%) |
| Guadalquivir | 8118 | 4370 | (53.83%) | 6 | (0.07%) |
| Ebro | 7642 | 4980 | (65.17%) | -32 | (-0.42%) |
| Duero | 7507 | 3971 | (52.89%) | -69 | (-0.92%) |
| Júcar | 3337 | 1188 | (35.60%) | 8 | (0.24%) |
| Miño-Sil | 3030 | 1441 | (47.56%) | -55 | (-1.82%) |
| Guadalete-Barbate | 1651 | 1065 | (64.51%) | 1 | (0.06%) |
| Med. Andaluza | 1174 | 780 | (66.44%) | 1 | (0.09%) |
| Segura | 1140 | 294 | (25.79%) | 4 | (0.35%) |
| Galicia Costa | 684 | 457 | (66.81%) | -7 | (-1.02%) |
| Cataluña Interna | 677 | 606 | (89.51%) | -4 | (-0.59%) |
| Cantabrico Occidental | 518 | 301 | (58.11%) | -18 | (-3.47%) |
| Tinto, Odiel y Piedras | 229 | 184 | (80.35%) | -1 | (-0.44%) |
| Cantabrico Oriental | 73 | 53 | (72.60%) | 0 | (0.00%) |
| Pais Vasco Interna | 21 | 14 | (66.67%) | 0 | (0.00%) |
