| Cuenca | Capacidad | Embalsada | Variacion | ||
| Tajo | 11056 | 6198 | (56.06%) | -68 | (-0.62%) |
| Guadiana | 9538 | 2412 | (25.29%) | -5 | (-0.05%) |
| Guadalquivir | 8028 | 1497 | (18.65%) | -4 | (-0.05%) |
| Ebro | 7802 | 4199 | (53.82%) | 147 | (1.88%) |
| Duero | 7600 | 4272 | (56.21%) | -10 | (-0.13%) |
| Miño-Sil | 3030 | 2444 | (80.66%) | -135 | (-4.46%) |
| Júcar | 2846 | 1305 | (45.85%) | -7 | (-0.25%) |
| Guadalete-Barbate | 1651 | 243 | (14.72%) | -2 | (-0.12%) |
| Med. Andaluza | 1174 | 238 | (20.27%) | -6 | (-0.51%) |
| Segura | 1140 | 222 | (19.47%) | -4 | (-0.35%) |
| Galicia Costa | 684 | 602 | (88.01%) | -22 | (-3.22%) |
| Cataluña Interna | 677 | 124 | (18.32%) | -3 | (-0.44%) |
| Cantabrico Occidental | 490 | 378 | (77.14%) | -8 | (-1.63%) |
| Tinto, Odiel y Piedras | 229 | 135 | (58.95%) | 0 | (0.00%) |
| Cantabrico Oriental | 73 | 57 | (78.08%) | 1 | (1.37%) |
| Pais Vasco Interna | 21 | 15 | (71.43%) | 1 | (4.76%) |
