Mason Reservoir water level history

Daily records since 1990 · Level today: 3,982.91 ft

Highest on record

5,210.71 ft

Sep 15, 2022

Lowest on record

2,589.28 ft

May 24, 2023

Today

3,982.91 ft

Oct 21, 2026

Years of data

since 1990

In short

Across 34 complete years, 2021 had the lowest average level (3,995.17 ft) and 1997 the highest (4,054.18 ft).

On average the lake is lowest in November (4,017.03 ft) and highest in June (4,047.49 ft).

Mason Reservoir level, all years

Loading chart…

Measured Normal range for the date (middle 50% of past years) Full pool

Lowest years

Years ranked by their lowest daily level.

20232,589.28 ft on May 24
20213,976.45 ft on Oct 22
20223,984.27 ft on Jan 1
20163,989.55 ft on Oct 13
20153,990.19 ft on Dec 3

Yearly highs and lows

Year	Average	Low	Low date	High	High date
2026 (290 days)	4,016.11	3,982.91	Oct 21	4,036.42	Apr 28
2025	4,033.92	4,020.28	Jan 1	4,055.44	Jun 9
2024	4,033.00	4,017.21	Oct 31	4,051.13	May 17
2023	4,017.05	2,589.28	May 24	4,051.24	Jun 16
2022	4,052.75	3,984.27	Jan 1	5,210.71	Sep 15
2021	3,995.17	3,976.45	Oct 22	4,018.06	Apr 27
2020	4,019.74	3,997.15	Nov 13	4,044.13	Jun 26
2019	4,022.84	3,998.88	Jan 2	4,050.38	Jun 14
2018	4,025.29	3,997.89	Oct 31	4,047.26	May 12
2017	4,034.78	3,993.93	Jan 1	4,061.89	Jun 23
2016	4,009.16	3,989.55	Oct 13	4,037.74	May 12
2015	4,013.82	3,990.19	Dec 3	4,035.94	Apr 21
2014	4,021.08	4,007.88	Jan 1	4,040.22	Jun 7
2013	4,025.49	4,005.63	Oct 30	4,043.96	May 15
2012	4,042.09	4,028.78	Oct 27	4,058.56	May 17
2011	4,049.94	4,039.31	Nov 2	4,066.45	Jun 30
2010	4,047.67	4,041.09	Jan 1	4,063.57	Jun 27
2009	4,047.08	4,037.82	Jan 1	4,062.64	Jun 26
2008	4,033.13	4,002.03	Jan 1	4,058.87	Jun 29
2007	4,024.30	3,996.65	Oct 19	4,049.08	Apr 25
2006	4,038.84	4,006.12	Jan 1	4,064.00	Jun 9
2005	4,018.08	4,001.26	Nov 3	4,042.07	Jun 1
2004	4,017.28	3,997.31	Jan 1	4,039.08	Jan 4
2003	4,010.21	3,993.67	Nov 5	4,036.11	Jun 16
2002	4,008.71	3,992.31	Oct 20	4,036.00	Jun 13
2001 (296 days)	4,012.62	3,988.76	Oct 28	4,041.30	Apr 7
2000	4,044.61	4,021.56	Sep 8	4,061.42	May 25
1999	4,049.02	4,038.77	Oct 26	4,065.70	Jun 21
1998	4,051.22	4,041.30	Oct 31	4,067.44	Jun 11
1997	4,054.18	4,044.35	Jan 1	4,067.59	May 22
1996	4,052.11	4,039.34	Oct 17	4,065.69	Jun 10
1995	4,041.09	4,010.59	Jan 6	4,059.73	Jul 2
1994	4,032.82	4,000.77	Oct 5	4,051.54	Apr 27
1993	4,038.89	3,997.44	Jan 1	4,066.82	Jun 13
1992	4,015.12	3,991.86	Oct 30	4,040.00	Apr 29
1991	4,032.08	4,018.17	Nov 1	4,049.03	Jul 4
1990 (318 days)	4,041.40	4,026.14	Sep 30	4,052.14	May 6

Levels in feet. Partial years show the number of days with data.

Monthly averages

Month	Average	Lowest	Highest
January	4,021.20	3,984.27	4,050.84
February	4,023.47	3,986.22	4,058.50
March	4,028.96	3,989.63	4,061.03
April	4,038.97	3,996.14	4,063.13
May	4,043.79	2,589.28	4,067.59
June	4,047.49	4,006.88	4,067.54
July	4,042.54	3,991.08	4,066.41
August	4,029.11	3,979.98	4,060.14
September	4,036.03	3,977.46	5,210.71
October	4,017.13	3,976.45	5,210.71
November	4,017.03	3,976.83	4,047.74
December	4,018.65	3,980.35	4,048.12

Download

Daily levels as CSV (13,309 rows; credit the original agencies listed below)