Water Area of California By Counties

Last updated on December 19th, 2023 at 10:24 am


The water area of the State of California is 7,916 sq mi or 20,501 sq km.) And this how the United States Census Bureau come about the total area covered by water bodies.

CA’s total area is put at 163,695 sq mi (or 423,967 sq km) while the land area (without water bodies) is put at 155,779 sq mi (or 403,466). Therefore, 163,695sq mi – 155,779 sq mi = 7,916 sq mi.

The water area of the 58 counties in California is exactly what this article is about since the land area and water area in the state make up the total area of the state.


The focus of this article is to make access to information by researchers easier so that they can find what they are looking for in a single place. This is what we call actionable info and it is free to use. Information and data matter for national development.

The list of the water area of Counties in California gives you an insight in descending order of how wet your County is. It also shows which part of California County has the largest water area.

How water area is calculated?

The water area only includes only the perennial water. Glacier, swamp, and intermittent water are categorized as part of the land area in CA.

Also Read:  10 Most Educated States in The U.S.

The combination of water and land area make up the total area and are treated by the state, country, county or local government areas as part of their territory. They are bound to defend against trespass.

So, don’t be surprised to see a nation or country defend their territory against external aggression on land, air, and the sea (water).

That’s by the side…

Which California Counties have the largest water area?

Located in Southern California, Santa Barbara County has the largest water area in the State of California, no wonder it is best known for its broad sandy beaches.

Sadly, most of the water area in Santa Barbara County is polluted. Sitting on a total area of 3,789 square miles, the county has 1,055.06 sq mi covered by water, thereby leaving 2,733.94 sq mi for the land area.

Does Santa Barbara County Supply California Water?

If you think the County of Santa Barbara should be the source of water to California or other states, the water area in this context doesn’t indicate that their water powers agricultural and domestic use.

Surprisingly, other data shows that Sacramento County which has just 28.73 sq mi of water area supplies more than 70% of California.

Los Angeles County, the 11th largest county by land area in CA, ranks No.2 by water area (691.72 sq mi) among the 58 Counties that make up California.

The County of Monterey is the third largest by water area. It has 489.28 sq mi covered by perennial water followed by Humboldt County and Mendocino respectively.

Also Read:  14 Countries in Oceania and Their Currency

Which County in California has the smallest Water Area?

Kings County has most of its total area covered by land, only 1.03 sq mi is covered by water. With its 1,392 sq mi total area, 1,390.97 sq mi is land area. It is followed by San Benito County with less than a 2 sq mi water area.

Alpine County has the third smallest water area with 4.66 sq mi. Colusa County and Sutter County are the fourth and fifth respectively.

The below table shows the water area of California by counties, according to the U.S. Census Bureau data

RankCountyWater Area AreaTotal Area
1Santa Barbara1,955.06 sq mi3,789 sq mi
2Los Angeles691.72 sq mi4,751 sq mi
3Monterey489.28 sq mi3,771 sq mi
4Humboldt483.81 sq mi4,052 sq mi
5Mendocino371.18 sq mi3,878 sq mi
6Ventura367.21 sq mi2,208 sq mi
7San Luis Obispo315.15 sq mi3,616 sq mi
8Marin307.58 sq mi828 sq mi
9Imperial306.46 sq mi4,482 sq mi
10San Mateo295.36 sq mi744 sq mi
11Modoc254.77 sq mi4,203 sq mi
12Del Norte223.77 sq mi1,230 sq mi
13Sonoma192.37 sq mi1,768 sq mi
14San Francisco184.98 sq mi231.89 sq mi
15Lassen178.66 sq mi4,720 sq mi
16Santa Cruz161.89 sq mi607 sq mi
17Orange155.16 sq mi948 sq mi
18Placer94.92 sq mi1,502 sq mi
19Riverside93.73 sq mi7,303 sq mi
20Constra Costa87.07 sq mi804 sq mi
21Solano84.17 sq mi906 sq mi
22Alameda83.54 sq mi821 sq mi
23Mono83.1 sq mi3,132 sq mi
24El Dorado78.15 sq mi1,786 sq mi
25Lake72.45 sq mi1,329 sq mi
26Shasta71.48 sq mi3,847 sq mi
27Siskiyou68.23 sq mi6,347 sq mi
28Plumas59.94 sq mi2,613 sq mi
29Tuolumne53.09 sq mi2,274 sq mi
30Fresno52.62 sq mi6,011 sq mi
31San Diego50.67 sq mi4,260.9 sq mi
32Merced41 sq mi1,979 sq mi
33Napa40.64 sq mi789 sq mi
34Butte40.51 sq mi1,677 sq mi
35San Bernardino36.99 sq mi20,105
36San Joaquin33.63 sq mi1,426 sq mi
37Inyo29.74 sq mi10,227 sq mi
38Trinity28.73 sq mi3,208 sq mi
38Sacramento28.73 sq mi965.27 sq mi
40Kern28.35 sq mi8,163 sq mi
41Stanislaus18.98 sq mi1,515 sq mi
42Calaveras16.98 sq mi1,037 sq mi
43Nevada16.24 sq mi974 sq mi
44Madera16.08 sq mi2,153 sq mi
45Tulare15.1 sq mi4,839 sq mi
46Mariposa14.16 sq mi1,463 sq mi
47Glenn13.03 sq mi1,327 sq mi
48Santa Clara12.92 sq mi1,304 sq mi
49Tehama12.8 sq mi2,962
50Yuba11.99 sq mi644 sq mi
51Amador11.42 sq mi606 sq mi
52Yolo9.27 sq mi1,024 sq i
53Sierra8.83 sq mi962 sq mi
54Sutter5.3 sq mi608 sq mi
55Colusa5.29 sq mi1,156 sq mi
56Alpine4.66 sq mi743 sq mi
57San Benito1.35 sq mi1,390 sq mi
58Kings1.03 sq mi1,392 sq mi
Source: census.gov/quickfacts

What part of California uses the most water?

Considering the concentration of tech firms in the San Francisco Bay and South Coast regions, demand for water is high.

Therefore, they rely heavily on water importation from other parts of the state. No wonder San Francisco is one of the most expensive cities in the U.S.

Which sector uses the highest water in California?

Due to the high output of the agricultural sector and the largest contributor to the economy of California, the demand for water by farmers is high, as such, agriculture consumes about 80% of all water used in CA.

According to the California Department of Water Resources, “California’s agricultural success would not be possible without irrigation” which shows how important water is in CA. For instance, water-intensive crops like almonds and alfalfa need irrigation to get the best produce.

Which state uses the most water?

The State of California uses the most water in the United States due to the state’s active and productive agricultural sector.

For instance, cdfa.ca.gov disclosed that California’s agricultural sector accounted for $20.8 billion in export in 2020. This sector consumed trillions of litres of water before such an economic feat could be achieved.

Do California farmers buy water?

California farmers buy water because the available one is not sufficient to take care of their needs through the farming season.

The cost of pumping or purchasing water from a supplier is expensive. Because of the cost of water, The Washington Post in a report says farmers abandon 400,000 acres of agricultural land unplanted in 2021 due to lack of water.


  1. QuickFacts from United State Census Bureau
  2. California Department of Water Resources. “Agricultural Water Use Efficiency”. water.ca.gov
  3. Scott Wilson (March 21, 2022). “As it enters a third year, California’s drought is strangling the farming industry”. washingtonpost.com

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