Lk Pillsbury — storage

Storage now, against this reservoir's own record

36.42 Mm³

Stored, September 2025

9th

Percentile among 83 Seps on record

-32.1%

Against the Sep 1991–2020 average

-22.9%

Change over the 12 months to 2025-09

Storage in September 2025 was lower than almost every other Sep on record, ranked against 83 other Seps held for this reservoir.

Storage, 1928–2025

Monthly mean storage

1,100 monthly values, 1928 to 2025

Monthly means of the publisher's daily record. Volume, not percentage of capacity: without a capacity whose definition is stated, fullness cannot be computed.

View the data behind this chart

Underlying data
Period	Lk Pillsbury Nr Potter Valley CA (Mm³)
October 1928	25.0
November 1928	15.0
December 1928	12.7
January 1929	23.2
February 1929	51.8
March 1929	55.3
April 1929	60.7
May 1929	70.4
June 1929	64.5
July 1929	53.2
August 1929	39.0
September 1929	26.0
October 1929	17.4
November 1929	11.3
December 1929	53.1
January 1930	99.1
February 1930	104
March 1930	111
April 1930	116
May 1930	116
June 1930	110
July 1930	98.3
August 1930	82.3
September 1930	67.0
October 1930	59.5
November 1930	50.1
December 1930	36.3
January 1931	37.3
February 1931	51.1
March 1931	61.3
April 1931	71.2
May 1931	67.6
June 1931	64.1
July 1931	57.9
August 1931	48.9
September 1931	38.0
October 1931	23.6
November 1931	7.99
December 1931	13.9
January 1932	91.2
February 1932	90.9
March 1932	108
April 1932	115
May 1932	116
June 1932	115
July 1932	109
August 1932	99.7
September 1932	90.5
October 1932	78.7
November 1932	60.9
December 1932	43.7
January 1933	46.0
February 1933	62.8
March 1933	97.5
April 1933	116
May 1933	116
June 1933	115
July 1933	106
August 1933	85.5
September 1933	66.1
October 1933	61.6
November 1933	64.0
December 1933	80.8
January 1934	91.7
February 1934	97.2
March 1934	110
April 1934	116
May 1934	115
June 1934	109
July 1934	97.4
August 1934	83.5
September 1934	69.8
October 1934	56.4
November 1934	56.5
December 1934	70.0
January 1935	90.3
February 1935	92.5
March 1935	102
April 1935	103
May 1935	114
June 1935	114
July 1935	105
August 1935	92.5
September 1935	79.1
October 1935	70.2
November 1935	64.4
December 1935	56.6
January 1936	87.1
February 1936	95.7
March 1936	96.8
April 1936	109
May 1936	115
June 1936	115
July 1936	107
August 1936	94.3
September 1936	80.8
October 1936	67.7
November 1936	56.4
December 1936	45.9
January 1937	35.4
February 1937	55.4
March 1937	96.6
April 1937	110
May 1937	115
June 1937	112
July 1937	106
December 1937	93.2
January 1938	91.0
February 1938	94.9
March 1938	95.2
April 1938	102
May 1938	114
June 1938	115
July 1938	108
November 1938	61.8
December 1938	73.2
January 1939	78.5
February 1939	87.4
March 1939	93.0
April 1939	105
August 1939	66.1
September 1939	50.9
November 1939	23.8
December 1939	29.5
January 1940	88.3
February 1940	104
March 1940	104
April 1940	110
May 1940	114
June 1940	115
July 1940	106
August 1940	93.8
November 1940	59.1
December 1940	70.4
January 1941	92.7
March 1941	95.5
April 1941	110
May 1941	115
September 1941	86.6
November 1941	61.0
December 1941	87.4
January 1942	92.1
February 1942	92.7
March 1942	90.8
April 1942	107
May 1942	116
June 1942	116
July 1942	111
August 1942	101
September 1942	90.0
October 1942	79.2
November 1942	77.4
December 1942	89.9
January 1943	91.7
February 1943	90.7
March 1943	103
April 1943	114
May 1943	115
June 1943	115
July 1943	109
August 1943	96.4
September 1943	83.7
October 1943	71.2
November 1943	57.8
December 1943	50.6
January 1944	67.0
February 1944	92.3
March 1944	113
April 1944	116
May 1944	116
June 1944	111
July 1944	100
August 1944	86.8
October 1944	58.7
November 1944	65.7
December 1944	86.8
January 1945	89.4
February 1945	97.0
March 1945	108
April 1945	114
May 1945	116
June 1945	113
July 1945	104
August 1945	89.3
September 1945	72.7
November 1945	63.1
December 1945	92.4
January 1946	91.0
February 1946	89.8
March 1946	98.5
April 1946	114
May 1946	115
June 1946	109
July 1946	98.4
August 1946	84.1
September 1946	70.4
October 1946	57.2
November 1946	50.1
December 1946	70.2
January 1947	64.0
March 1947	114
April 1947	116
May 1947	115
June 1947	115
July 1947	108
August 1947	97.3
September 1947	84.2
October 1947	73.4
November 1947	69.7
December 1947	58.3
January 1948	84.3
February 1948	91.2
March 1948	102
April 1948	115
May 1948	115
June 1948	116
July 1948	114
August 1948	105
November 1948	66.7
December 1948	66.4
January 1949	70.9
February 1949	75.9
March 1949	93.3
April 1949	114
May 1949	116
June 1949	115
July 1949	108
October 1949	70.1
November 1949	60.2
December 1949	46.7
February 1950	91.1
March 1950	97.3
April 1950	109
May 1950	116
June 1950	116
July 1950	107
August 1950	95.3
January 1951	92.3
February 1951	91.7
March 1951	91.9
April 1951	96.1
May 1951	104
June 1951	102
July 1951	92.1
December 1951	90.8
January 1952	91.5
February 1952	92.4
March 1952	91.3
April 1952	101
May 1952	111
June 1952	110
July 1952	101
December 1952	86.0
January 1953	94.2
February 1953	90.3
March 1953	93.5
April 1953	108
May 1953	116
June 1953	115
July 1953	104
January 1954	74.4
February 1954	91.8
March 1954	93.4
April 1954	112
May 1954	114
June 1954	106
July 1954	96.0
April 1955	98.1
May 1955	114
June 1955	110
July 1955	95.3
January 1956	93.7
February 1956	92.3
March 1956	90.8
April 1956	97.5
May 1956	109
June 1956	110
July 1956	97.9
March 1957	96.5
April 1957	114
May 1957	115
June 1957	115
July 1957	105
August 1957	90.6
October 1957	81.0
November 1957	85.7
December 1957	86.3
January 1958	91.5
February 1958	95.4
March 1958	91.5
April 1958	93.0
May 1958	113
June 1958	115
July 1958	107
August 1958	92.4
September 1958	74.7
October 1958	53.4
November 1958	32.3
December 1958	21.8
January 1959	70.2
February 1959	90.7
March 1959	91.5
April 1959	108
May 1959	115
June 1959	107
July 1959	84.3
August 1959	58.9
September 1959	39.4
October 1959	34.0
November 1959	26.5
December 1959	20.6
January 1960	26.2
February 1960	78.8
March 1960	101
April 1960	106
May 1960	107
June 1960	106
July 1960	91.5
August 1960	76.1
September 1960	66.7
October 1960	49.7
November 1960	31.7
December 1960	67.4
January 1961	76.7
February 1961	83.9
March 1961	98.2
April 1961	107
May 1961	107
June 1961	104
July 1961	95.9
August 1961	86.9
September 1961	70.4
October 1961	47.7
November 1961	29.9
December 1961	50.9
January 1962	49.7
February 1962	73.9
March 1962	83.2
April 1962	93.5
May 1962	105
June 1962	104
July 1962	91.9
August 1962	75.0
September 1962	58.9
October 1962	69.0
November 1962	68.6
December 1962	81.4
January 1963	76.6
February 1963	83.3
March 1963	86.4
April 1963	104
May 1963	105
June 1963	105
July 1963	94.9
August 1963	80.3
September 1963	64.2
October 1963	50.5
November 1963	55.5
December 1963	70.1
January 1964	70.2
February 1964	81.5
March 1964	78.1
April 1964	85.4
May 1964	91.4
June 1964	91.4
July 1964	85.0
August 1964	73.3
September 1964	61.0
October 1964	44.6
November 1964	37.9
December 1964	66.8
January 1965	85.8
February 1965	83.1
March 1965	90.6
April 1965	105
May 1965	106
June 1965	102
July 1965	88.6
August 1965	72.7
September 1965	55.1
October 1965	33.5
November 1965	31.4
December 1965	47.7
January 1966	82.0
February 1966	83.1
March 1966	84.4
April 1966	102
May 1966	107
June 1966	104
July 1966	93.4
August 1966	77.0
September 1966	58.8
October 1966	36.6
November 1966	34.5
December 1966	83.2
January 1967	82.9
February 1967	83.1
March 1967	83.2
April 1967	92.9
May 1967	101
June 1967	106
July 1967	93.8
August 1967	73.2
September 1967	51.4
October 1967	33.4
November 1967	17.7
December 1967	28.6
January 1968	60.7
February 1968	84.2
March 1968	89.4
April 1968	97.6
May 1968	105
June 1968	105
July 1968	92.8
August 1968	76.0
September 1968	60.4
October 1968	43.1
November 1968	25.5
December 1968	48.0
January 1969	86.3
February 1969	85.0
March 1969	83.9
April 1969	90.9
May 1969	107
June 1969	104
July 1969	93.0
August 1969	77.4
September 1969	59.2
October 1969	38.2
November 1969	18.9
December 1969	46.0
January 1970	87.2
February 1970	83.6
March 1970	83.0
April 1970	88.5
May 1970	94.7
June 1970	91.7
July 1970	82.3
August 1970	70.5
September 1970	55.7
October 1970	34.0
November 1970	30.1
December 1970	83.0
January 1971	84.5
February 1971	82.3
March 1971	88.4
April 1971	103
May 1971	106
June 1971	97.6
July 1971	91.0
August 1971	84.4
September 1971	76.5
October 1971	63.6
November 1971	52.3
December 1971	51.8
January 1972	67.7
February 1972	83.2
March 1972	88.9
April 1972	104
May 1972	105
June 1972	103
July 1972	93.9
August 1972	74.7
September 1972	58.5
October 1972	38.3
November 1972	28.5
December 1972	47.9
January 1973	84.3
February 1973	83.9
March 1973	83.0
April 1973	87.7
May 1973	98.8
June 1973	98.1
July 1973	88.4
August 1973	75.5
September 1973	60.0
October 1973	44.3
November 1973	75.5
December 1973	84.3
January 1974	85.0
February 1974	82.9
March 1974	85.6
April 1974	99.9
May 1974	106
June 1974	98.4
July 1974	89.4
August 1974	83.6
September 1974	70.5
October 1974	49.5
November 1974	29.0
December 1974	18.6
January 1975	29.9
February 1975	71.2
March 1975	85.6
April 1975	97.5
May 1975	106
June 1975	104
July 1975	96.1
August 1975	86.0
September 1975	70.4
October 1975	49.6
November 1975	35.6
December 1975	25.3
January 1976	13.8
February 1976	16.9
March 1976	67.9
April 1976	86.8
May 1976	99.7
June 1976	98.5
July 1976	92.0
August 1976	83.6
September 1976	72.4
October 1976	52.1
November 1976	32.3
December 1976	15.3
January 1977	11.8
February 1977	13.4
March 1977	19.8
April 1977	26.5
May 1977	28.2
June 1977	27.4
July 1977	23.1
August 1977	17.1
September 1977	12.6
October 1977	11.8
November 1977	16.0
December 1977	52.0
January 1978	86.4
February 1978	85.2
March 1978	84.7
April 1978	100
May 1978	106
June 1978	101
July 1978	90.8
August 1978	80.4
September 1978	68.8
October 1978	53.2
November 1978	32.4
December 1978	13.1
January 1979	24.9
February 1979	48.4
March 1979	90.7
April 1979	101
May 1979	107
June 1979	101
July 1979	92.1
August 1979	80.0
September 1979	64.0
October 1979	44.3
November 1979	52.5
December 1979	68.1
January 1980	85.5
February 1980	84.6
March 1980	83.8
April 1980	99.4
May 1980	104
June 1980	98.0
July 1980	89.2
August 1980	77.4
September 1980	61.2
October 1980	38.6
November 1980	15.8
December 1980	23.8
January 1981	25.0
February 1981	81.9
March 1981	85.3
April 1981	97.6
May 1981	95.6
June 1981	89.3
July 1981	78.6
August 1981	68.9
September 1981	57.5
October 1981	37.2
November 1981	56.2
December 1981	85.4
January 1982	84.2
February 1982	85.0
March 1982	84.0
April 1982	89.8
May 1982	102
June 1982	101
July 1982	91.3
August 1982	80.8
September 1982	65.9
October 1982	53.1
November 1982	57.8
December 1982	84.4
January 1983	83.8
February 1983	85.8
March 1983	86.6
April 1983	83.7
May 1983	83.5
June 1983	85.0
July 1983	77.2
August 1983	57.5
September 1983	48.0
October 1983	43.2
November 1983	67.5
December 1983	85.3
January 1984	82.2
February 1984	81.2
March 1984	82.4
April 1984	86.9
May 1984	97.1
June 1984	97.5
July 1984	93.5
August 1984	79.4
September 1984	67.7
October 1984	49.6
November 1984	60.6
December 1984	81.3
January 1985	71.2
February 1985	75.1
March 1985	77.9
April 1985	98.2
May 1985	102
June 1985	98.4
July 1985	86.7
August 1985	71.9
September 1985	56.5
October 1985	26.2
November 1985	11.2
December 1985	29.3
January 1986	46.1
February 1986	80.0
March 1986	76.4
April 1986	80.5
May 1986	88.0
June 1986	85.7
July 1986	77.3
August 1986	67.0
September 1986	56.6
October 1986	40.0
November 1986	24.3
December 1986	17.8
January 1987	22.7
February 1987	57.1
March 1987	75.1
April 1987	74.8
May 1987	75.7
June 1987	70.0
July 1987	61.9
August 1987	52.6
September 1987	43.6
October 1987	34.6
November 1987	26.8
December 1987	65.3
January 1988	75.0
February 1988	72.6
March 1988	67.2
April 1988	63.7
May 1988	65.4
June 1988	61.3
July 1988	52.6
August 1988	42.1
September 1988	31.9
October 1988	24.0
November 1988	27.3
December 1988	38.3
January 1989	44.3
February 1989	51.0
March 1989	79.7
April 1989	97.6
May 1989	93.9
June 1989	87.9
July 1989	78.8
August 1989	67.1
September 1989	56.1
October 1989	43.6
November 1989	39.4
December 1989	29.6
January 1990	42.5
February 1990	51.9
March 1990	70.2
April 1990	76.0
May 1990	79.2
June 1990	97.2
July 1990	93.4
August 1990	86.2
September 1990	71.8
October 1990	50.3
November 1990	28.6
December 1990	19.3
January 1991	17.0
February 1991	21.4
March 1991	75.8
April 1991	95.3
May 1991	97.7
June 1991	93.3
July 1991	84.9
August 1991	74.9
September 1991	66.5
October 1991	51.1
November 1991	33.1
December 1991	27.0
January 1992	30.6
February 1992	57.3
March 1992	80.9
April 1992	94.6
May 1992	95.7
June 1992	87.4
July 1992	78.9
August 1992	67.3
September 1992	56.4
October 1992	45.8
November 1992	38.8
December 1992	62.4
January 1993	77.1
February 1993	76.2
March 1993	75.6
April 1993	88.8
May 1993	98.3
June 1993	98.1
July 1993	90.7
August 1993	81.6
September 1993	67.8
October 1993	46.2
November 1993	27.5
December 1993	27.2
January 1994	26.3
February 1994	43.2
March 1994	67.4
April 1994	67.4
May 1994	70.2
June 1994	68.8
July 1994	62.5
August 1994	51.7
September 1994	42.3
October 1994	34.8
November 1994	30.5
December 1994	37.4
January 1995	73.1
February 1995	75.2
March 1995	78.4
April 1995	83.4
May 1995	94.0
June 1995	96.2
July 1995	95.3
August 1995	89.1
September 1995	80.8
October 1995	71.6
November 1995	63.0
December 1995	65.2
January 1996	75.5
February 1996	76.6
March 1996	81.8
April 1996	95.6
May 1996	97.5
June 1996	97.0
July 1996	91.7
August 1996	79.6
September 1996	62.1
October 1996	39.6
November 1996	28.7
December 1996	66.8
January 1997	78.0
February 1997	74.5
March 1997	76.3
April 1997	84.0
May 1997	85.2
June 1997	81.6
July 1997	73.3
August 1997	62.0
September 1997	49.8
October 1997	36.9
November 1997	28.5
December 1997	44.2
January 1998	73.3
February 1998	80.1
March 1998	77.2
April 1998	85.6
May 1998	94.6
June 1998	97.6
July 1998	94.3
August 1998	86.1
September 1998	72.0
October 1998	51.6
November 1998	37.5
December 1998	71.5
January 1999	68.4
February 1999	77.3
March 1999	76.0
April 1999	89.1
May 1999	97.5
June 1999	93.5
July 1999	83.7
August 1999	74.0
September 1999	63.6
October 1999	51.5
November 1999	39.4
December 1999	32.8
January 2000	48.4
February 2000	77.4
March 2000	76.3
April 2000	89.2
May 2000	98.5
June 2000	93.5
July 2000	83.8
August 2000	73.3
September 2000	62.1
October 2000	49.9
November 2000	33.0
December 2000	22.7
January 2001	21.9
February 2001	36.6
March 2001	81.3
April 2001	95.0
May 2001	91.6
June 2001	82.1
July 2001	75.5
August 2001	67.0
September 2001	57.8
October 2001	49.6
November 2001	45.0
December 2001	75.4
January 2002	75.3
February 2002	73.7
March 2002	74.5
April 2002	79.4
May 2002	77.6
June 2002	71.1
July 2002	63.3
August 2002	55.1
September 2002	47.2
October 2002	39.3
November 2002	34.6
December 2002	57.9
January 2003	76.6
February 2003	74.2
March 2003	84.3
April 2003	96.5
May 2003	97.6
June 2003	96.6
July 2003	89.2
August 2003	78.9
September 2003	64.9
October 2003	46.5
November 2003	36.5
December 2003	63.1
January 2004	75.2
February 2004	77.1
March 2004	78.0
April 2004	92.3
May 2004	96.1
June 2004	88.3
July 2004	79.2
August 2004	67.8
September 2004	56.3
October 2004	45.1
November 2004	34.2
December 2004	45.5
January 2005	72.7
February 2005	79.8
March 2005	82.7
April 2005	94.1
May 2005	97.8
June 2005	97.9
July 2005	95.3
August 2005	85.8
September 2005	74.9
October 2005	59.1
November 2005	53.7
December 2005	70.5
January 2006	70.6
February 2006	69.5
March 2006	70.6
April 2006	77.6
May 2006	88.3
June 2006	85.3
July 2006	77.0
August 2006	65.6
September 2006	53.4
October 2006	39.9
November 2006	31.2
December 2006	37.0
January 2007	55.0
February 2007	62.6
March 2007	74.1
April 2007	81.1
May 2007	78.8
June 2007	69.5
July 2007	59.1
August 2007	47.6
September 2007	36.7
October 2007	29.4
November 2007	25.7
December 2007	25.6
January 2008	62.3
February 2008	69.2
March 2008	68.8
April 2008	75.0
May 2008	77.9
June 2008	69.4
July 2008	59.3
August 2008	47.9
September 2008	36.7
October 2008	29.0
November 2008	24.5
December 2008	18.6
January 2009	19.3
February 2009	26.5
March 2009	75.6
April 2009	85.1
May 2009	87.2
June 2009	79.5
July 2009	70.2
August 2009	59.0
September 2009	48.5
October 2009	41.2
November 2009	36.8
December 2009	33.1
January 2010	51.7
February 2010	68.8
March 2010	68.5
April 2010	83.1
May 2010	86.6
June 2010	89.8
July 2010	86.0
August 2010	75.6
September 2010	63.7
October 2010	56.9
November 2010	57.5
December 2010	65.9
January 2011	68.0
February 2011	67.2
March 2011	70.6
April 2011	82.8
May 2011	90.1
June 2011	89.7
July 2011	87.0
August 2011	77.4
September 2011	63.2
October 2011	47.2
November 2011	36.8
December 2011	29.7
January 2012	28.2
February 2012	41.2
March 2012	59.0
April 2012	83.1
May 2012	82.5
June 2012	71.0
July 2012	60.9
August 2012	49.5
September 2012	38.6
October 2012	30.5
November 2012	28.5
December 2012	69.4
January 2013	67.7
February 2013	66.9
March 2013	67.9
April 2013	72.2
May 2013	65.5
June 2013	56.4
July 2013	48.9
August 2013	40.0
September 2013	31.5
October 2013	24.0
November 2013	18.8
December 2013	13.1
January 2014	10.6
February 2014	19.2
March 2014	63.8
April 2014	87.2
May 2014	80.0
June 2014	72.9
July 2014	65.6
August 2014	57.7
September 2014	49.1
October 2014	41.2
November 2014	37.1
December 2014	61.8
January 2015	65.8
February 2015	67.4
March 2015	63.8
April 2015	57.4
May 2015	46.6
June 2015	39.3
July 2015	32.9
August 2015	26.7
September 2015	21.2
October 2015	17.1
November 2015	15.0
December 2015	31.9
January 2016	68.9
February 2016	68.0
March 2016	70.5
April 2016	72.6
May 2016	67.2
June 2016	57.0
July 2016	47.4
August 2016	39.8
September 2016	33.2
October 2016	29.5
November 2016	38.6
December 2016	62.5
January 2017	71.2
February 2017	72.7
March 2017	73.1
April 2017	86.2
May 2017	88.9
June 2017	79.3
July 2017	69.3
August 2017	56.9
September 2017	44.7
October 2017	36.7
November 2017	32.9
December 2017	28.7
January 2018	30.2
February 2018	40.8
March 2018	54.8
April 2018	89.0
May 2018	87.6
June 2018	78.0
July 2018	70.8
August 2018	63.1
September 2018	55.8
October 2018	48.6
November 2018	42.4
December 2018	43.7
January 2019	65.6
February 2019	73.4
March 2019	72.8
April 2019	87.0
May 2019	92.7
June 2019	92.6
July 2019	87.7
August 2019	77.6
September 2019	67.0
October 2019	58.3
November 2019	50.7
December 2019	53.7
January 2020	57.0
February 2020	68.8
March 2020	66.9
April 2020	67.2
May 2020	65.1
June 2020	60.1
July 2020	55.1
August 2020	48.4
September 2020	42.5
October 2020	35.8
November 2020	30.2
December 2020	23.9
January 2021	23.8
February 2021	39.0
March 2021	49.4
April 2021	52.0
May 2021	46.2
June 2021	42.1
July 2021	38.1
August 2021	33.6
September 2021	29.7
October 2021	34.1
November 2021	65.4
December 2021	69.5
January 2022	70.8
February 2022	69.2
March 2022	66.4
April 2022	67.6
May 2022	74.0
June 2022	66.5
July 2022	58.2
August 2022	51.1
September 2022	45.6
October 2022	40.1
November 2022	36.0
December 2022	43.1
January 2023	73.4
February 2023	70.3
March 2023	73.3
April 2023	71.6
May 2023	70.3
June 2023	68.0
July 2023	63.8
August 2023	55.7
September 2023	47.5
October 2023	42.1
November 2023	39.6
December 2023	45.4
January 2024	71.6
February 2024	73.0
March 2024	72.7
April 2024	71.0
May 2024	69.4
June 2024	63.2
July 2024	58.0
August 2024	52.4
September 2024	47.2
October 2024	41.9
November 2024	49.8
December 2024	72.0
January 2025	70.7
February 2025	73.7
March 2025	71.6
April 2025	71.2
May 2025	67.5
June 2025	58.1
July 2025	48.8
August 2025	40.7
September 2025	36.4

The reservoir's year

Seasonal storage profile

Each calendar month's reference average, against the most recent year

1991–2020 average
Most recent 12 months

Twelve separate averages, one per calendar month. A January average describes Januaries only. Months are plotted 1–12.

View the data behind this chart

Underlying data
Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	56.1	70.7
Feb	62.8	73.7
Mar	72.9	71.6
Apr	83.9	71.2
May	85.8	67.5
Jun	81.1	58.1
Jul	74.0	48.8
Aug	64.2	40.7
Sep	53.7	36.4
Oct	42.8	41.9
Nov	35.7	49.8
Dec	45.6	72.0

Rate and persistence

-0.90 Mm³

Mean drawdown per month over 12 months

11 of 24

Months in the last two years below the 20th percentile for their own month

Rates are computed only across an unbroken run of months, so a rate is never divided by a period in which some of the change was not observed. Percentile counts compare each month with the same calendar month in every other year held.

Location

Lk Pillsbury Nr Potter Valley CA

Gauge location

Where this comes from

1,100 monthly observations 1928–2025 Mm³

Spatially aggregatedHigh confidenceSeptember 2025

Source: USGS — National Water Information System, 11470000. Licence: Open.

Method: Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Reservoir storage is managed as well as observed: a drawdown may reflect an operating rule, flood-control rule curve or scheduled release rather than a shortage. Compare a month against the same month in other years, and do not read a fall as a supply signal without knowing the operating regime.

Retrieved 25 August 2026.

Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.