California has a vast network of local, state and federal reservoirs that store and supply water to cities and farms across the state. Water stored in the reservoirs typically makes up about 60% of the state’s total water supply.
Rain and snowfall during the rainier months of the year between November and March are critical for the reservoirs and their ability to supply water during drier months. Following consecutive years of drought, many of the reservoirs remain thirsty.
The Chronicle is tracking daily water storage levels at 48 of the state’s major water supply reservoirs compared with their historical averages (1991 to 2020). The storage level is shown as percentages of total storage capacity for each reservoir. The charts are updated daily at 8:00 a.m. to reflect the most recent data.
Reservoir capacity:
Daily storage as a share of average:
About the data
Reservoir data is from the California Data Exchange Center. One acre-foot is equivalent to 325,851 gallons.