| Cuenca | Capacidad | Embalsada | Variación | ||
| Tajo | 11056 | 8929 | (80.76%) | -182 | (-1.65%) |
| Guadiana | 9538 | 6421 | (67.32%) | -67 | (-0.70%) |
| Guadalquivir | 8028 | 4499 | (56.04%) | -88 | (-1.10%) |
| Ebro | 7802 | 6632 | (85.00%) | -190 | (-2.44%) |
| Duero | 7602 | 6585 | (86.62%) | -161 | (-2.12%) |
| Miño-Sil | 3030 | 2532 | (83.56%) | -52 | (-1.72%) |
| Júcar | 2846 | 1728 | (60.72%) | -20 | (-0.70%) |
| Guadalete-Barbate | 1651 | 848 | (51.36%) | -12 | (-0.73%) |
| Med. Andaluza | 1174 | 652 | (55.54%) | -7 | (-0.60%) |
| Segura | 1140 | 349 | (30.61%) | -8 | (-0.70%) |
| Galicia Costa | 684 | 461 | (67.40%) | -4 | (-0.58%) |
| Cataluña Interna | 677 | 543 | (80.21%) | -7 | (-1.03%) |
| Cantábrico Occidental | 490 | 414 | (84.49%) | -8 | (-1.63%) |
| Tinto, Odiel y Piedras | 229 | 197 | (86.03%) | -2 | (-0.87%) |
| Cantábrico Oriental | 73 | 60 | (82.19%) | 0 | (0.00%) |
| País Vasco Interna | 21 | 19 | (90.48%) | -1 | (-4.76%) |
