Long term drought impacts continued through the month of May, though the largest of the reservoirs in northern interior California were at or above normal levels due to a significant mountain snow pack melting. Lake Shasta was 107% of normal by the end of the month, Lake Oroville was 111%, Folsom Lake was 101%, and Don Pedro was 99%. New Melones continued to lag behind the other significant area reservoirs and was only 41% of normal. On April 21st, the Department of Water Resources increased water delivery projections to the State Water Project to 60%, up from the 45% estimate in late March.
The U.S. Drought Monitor showed improvement from extreme to severe drought across the southern Sacramento Valley; the northern and central Sacramento Valley and the northern Sierra improved from severe to moderate drought, while Shasta County improved from moderate drought to abnormally dry by the end of the month. The remainder of the Central and northern portion of the Southern Sierra Nevada mountain areas remained in the severe to extreme drought. There was improvement from exceptional to extreme in the Sierra south of Highway 50.
April-July forecasts remained the same or dropped when compared to the April 1 forecast.  The changes were -5, and 0 respectively in the Sacramento and San Joaquin regions.  Despite the presence last Fall of warmer-than-normal tropical sea surface temperatures and the thought by some that they would contribute to a very wet California winter, the April-July forecasts for the three main Sierra regions were below average.   The water year forecasts are 102 and 91 percent of average for the Sacramento and San Joaquin regions.
Groundwater aquifers recharged much more slowly than the surface reservoirs, with many in the Central Valley still falling toward record levels.
Governor Jerry Brown declared a drought emergency for the entire state of California January 17, 2014 and this continued to be in effect. Governor Brown issued an executive order on May 9, 2016 that built on temporary statewide emergency water restrictions to establish longer-term water conservation measures, including permanent monthly water use reporting, new permanent water use standards in California communities and banned clearly wasteful practices such as hosing off sidewalks, driveways and other hardscapes.
Local Emergency Proclamations remain for Butte, Colusa, Calaveras, El Dorado, Glenn, Plumas, San Joaquin, Shasta, Stanislaus, Sutter, Tuolumne, and Yuba. The cities of Live Oak (Sutter County), Lodi (San Joaquin County), Manteca (San Joaquin County), Portola (Plumas County), Ripon (San Joaquin County), and
West Sacramento (Yolo County). Drought task forces have been established in Butte, Lake, Nevada, Placer, Plumas, Sacramento, San Joaquin, Stanislaus, Sutter, Tehama, Tuolumne, and Yolo counties to coordinate response to the drought.
Mandatory water reductions of 25 percent as ordered by Governor Brown were suspended in May due to the improved reservoir levels. Communities would set reduction guidelines based on their own projection of water supplies and the state could review the projections and impose restrictions on communities it determines were being unrealistic. In spite of the removal of the mandatory reductions, the State Water Resources Control Board announced that Californians reduced residential water use by 28 percent in May, compared with the same month in 2013.
The state continued to supply food assistance to those impacted by the drought, along with California Disaster Assistance Act money for those who have lost drinking water due to dry wells. Nonprofit organizations in the San Joaquin Valley struggled to meet the needs of their clients for drought-related programs.

Drought in CENTRAL SACRAMENTO VALLEY, CALIFORNIA
From 01-MAY-16 00:00:00 to 31-MAY-16 23:59:00 (PST-8)
Reported by: State Official

The Household Water Supply Shortage Reporting System indicated there were some homes without well water due to dry wells with 25 in Glenn County, 3 lower than in April. Colusa County had 4, 5 less than in April. Butte County continued at 0 wells.

Drought in SOUTHERN SACRAMENTO VALLEY, CALIFORNIA
From 01-MAY-16 00:00:00 to 31-MAY-16 23:59:00 (PST-8)
Reported by: State Official

The Household Water Supply Shortage Reporting System indicated there were some homes without well water due to dry wells, with 1 in Yolo County, which was 2 less than April. There was 1 in Sacramento County, unchanged from April.

Drought in CARQUINEZ STRAIT AND DELTA, CALIFORNIA
From 01-MAY-16 00:00:00 to 31-MAY-16 23:59:00 (PST-8)
Reported by: State Official

The Household Water Supply Shortage Reporting System had 1 home without well water in Solano County, unchanged from April.

Drought in NORTHERN SAN JOAQUIN VALLEY, CALIFORNIA
From 01-MAY-16 00:00:00 to 31-MAY-16 23:59:00 (PST-8)
Reported by: State Official

The Household Water Supply Shortage Reporting System indicated there were some homes without well water due to dry wells, with 228 in Stanislaus County, unchanged since April, and 10 in San Joaquin County, 15 less than April. However, many communities in the Northern San Joaquin valley were still receiving food assistance as a direct result of the drought.

Drought in MOTHERLODE/CAMPTONVILLE TO GROVELAND, CALIFORNIA
From 01-MAY-16 00:00:00 to 31-MAY-16 23:59:00 (PST-8)
Reported by: State Official

The Household Water Supply Shortage Reporting System had Calavereas County with 1 household, Tuolumne County had 238 households, unchanged from April.

Drought in NORTHERN SACRAMENTO VALLEY, CALIFORNIA
From 01-MAY-16 00:00:00 to 31-MAY-16 23:59:00 (PST-8)
Reported by: State Official

The Household Water Supply Shortage Reporting System indicated there were still some homes without well water due to dry wells, with 3 in Shasta County, one more than in March. Tehama County was 34, unchanged from April.