| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 5164 | (46.71%) | -286 | (-2.59%) |
| Guadiana | 9261 | 3184 | (34.38%) | -75 | (-0.81%) |
| Guadalquivir | 8113 | 2767 | (34.11%) | -85 | (-1.05%) |
| Ebro | 7919 | 5771 | (72.87%) | -210 | (-2.65%) |
| Duero | 7507 | 5110 | (68.07%) | -181 | (-2.41%) |
| Miño-Sil | 3030 | 1757 | (57.99%) | -64 | (-2.11%) |
| Júcar | 2846 | 1636 | (57.48%) | -29 | (-1.02%) |
| Guadalete-Barbate | 1651 | 628 | (38.04%) | -14 | (-0.85%) |
| Med. Andaluza | 1174 | 550 | (46.85%) | -10 | (-0.85%) |
| Segura | 1140 | 541 | (47.46%) | -8 | (-0.70%) |
| Galicia Costa | 684 | 523 | (76.46%) | 2 | (0.29%) |
| Cataluña Interna | 677 | 575 | (84.93%) | -13 | (-1.92%) |
| Cantabrico Occidental | 518 | 430 | (83.01%) | -2 | (-0.39%) |
| Tinto, Odiel y Piedras | 229 | 169 | (73.80%) | -3 | (-1.31%) |
| Cantabrico Oriental | 73 | 57 | (78.08%) | 1 | (1.37%) |
| Pais Vasco Interna | 21 | 17 | (80.95%) | -1 | (-4.76%) |
