California's commercial cannabis laws, as established through the Medicinal and Adult Use Cannabis Regulation and Safety Act (MAUCRSA), have always contained the acutely problematic provisions of so-called local control as well as the express exclusion of cannabis from the California Environmental Quality Act (CEQA) exemptions endowed to all other agricultural crops. This has created an unworkable dynamic for California's legal cannabis mixed light and outdoor cultivators who are uniquely vulnerable to baseless claims of excessive water use. Such claims are routinely deployed as a trojan horse by those ideologically opposed to cannabis legalization in order to prevent the permitting of specific projects, as well as to obstruct the effectuation of necessary local ordinances.

In order to really understand the speciousness of these arguments, it is important to evaluate the water use of other agricultural activities in California. As a baseline fact, agricultural activities are the primary consumer of water resources in California,accounting for approximately 80% of all water used for businesses and homes in the state.1 Since the scale of consumption is so vast, common units like gallons and liters don't suffice to measure water use. Instead, agricultural water use is often measured in acre feet.

An acre foot is the amount of water required to cover one acre of land up to one foot. This is equivalent to 43,560 cubic feet or 325,851 gallons of water; or roughly half an Olympic sized swimming pool.2

Cannabis cultivation, like almost all other agricultural activities, consumes water. However, cannabis actually uses a relatively small amount of California's water when compared to the average water consumed to grow an acre of California's other major agricultural crops.3

Average Acre Feet of Water Required to Cultivate One Acre of Various Crops

Figure 1: Average acre feet of water, shown to approximate scale, required to cultivate a single acre of various crops in California.

The Scale of Cannabis Cultivation

An examination of cannabis' water usage doesn't stop at scrutinizing the average acre feet of water required to cultivate an acre of cannabis and other important crops in California. To reveal the entire picture, we must look at the scale of cultivation of each crop.

As of August 19, 2021, there were only 8,081 active cannabis cultivation licenses issued in California.4 Assuming ALL 8,081 licensees are cultivating the maximum permissible area, which is a likely overestimation, we calculated a maximum cultivated area of 2,078 acres.4 Even with this likely overestimation of cannabis farm canopy, this is still a paltry amount of acreage relative to other agricultural activities.

For reference, the assumed 2,078 acres of legal cannabis cultivation is approximately twice the size of Golden Gate Park in San Francisco or half the size of Griffith Park in Los Angeles.5

Perhaps, the comparison to other crops is more illustrative. California cultivates approximately 1 million acres of alfalfa, which is predominantly used for livestock feed.6 California also cultivates approximately 830,000 acres of irrigated pasture.6 For perspective, this total area-1,830,000 acres-represents an area 60 times the size of the City of San Francisco. And this is just the land area used to grow alfalfa and irrigated pasture for livestock.6

California also devoted over 1,260,000 acres to almond cultivation in 2020.7 This area is nearly as big as all of California's state parks combined.7 In 2020, Grapes were cultivated on 895,000 acres: an area that easily dwarfs Yosemite National Park.8

Again, California, even with the likely over estimation of plant canopy as described above, only has 2,078 acres of licensed cannabis canopy. This is 0.1% of the irrigated land used to grow alfalfa and pasture for livestock.

Total Land Under Cultivation Of Various Crops in California

Figure 2: Land area (acres) under cultivation of various crops in California, shown to scale.

The Water Used By California's Cannabis Industry

California's legal and regulated cannabis industry only uses a small amount of water relative to other agricultural activities. Based on our calculations, alfalfa and irrigated pasture cultivation in California uses about 8,403,000 acre feet of water. This is 16 times the entire water usage of Los Angeles.9 Similarly, in 2020, almond cultivation, another huge consumer of California's agricultural water, used about 4,914,000 acre feet of water. This is more than the volume of Lake Shasta (4,552,000 acre feet), California's largest freshwater reservoir.9 Assuming an average 1.4 acre feet of water required to grow an acre of cannabis (Figure 1), California's legal cannabis canopy consumes approximately 2,909 acre feet of water or 0.03% of the water used by alfalfa and irrigated pasture.9

Total Water Consumed By Various Crops in California

Figure 3: Annual water usage (in acre feet) of various crops as well as the City of Los Angeles, shown to scale.

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[1] Agriculture Consumes a Majority of California's Non-Environmental Water

In California water is shared across three main sectors: environmental (~50%), agricultural (~40%), and 10% urban. More than nine million acres of farmland are irrigated in California. This represents roughly 80% of all water used for businesses and homes, i.e. non-environmental needs.

Relevant Sources:

[2] An Acre Foot Compared to the Volume of an Olympic-sized Swimming Pool

An Acre Foot is 0.49 times the volumes of an (official) Olympic-sized swimming pool.

Volume (Cubic Feet) Volume (U.S. Gallons)
Acre Foot 43,560 325,853.38
Olympic Swimming Pool 88,000 660,000.00

Table 2: An Acre Foot Compared to an Olympic-sized Swimming Pool

Relevant Source:

FINA (Fédération Internationale De Natation). (2021). (publication). FINA Facilities Rules. Facilities Rules 2017 - 2021. Lausanne, Switzerland. Retrieved from:

[3] Average Acre Feet Required to Cultivate An Acre of Various Crops in California

Relevant Sources:

[4] Cultivation Area (Canopy Size) of All Active California State Cannabis Cultivation Licenses

To calculate the total area devoted to cannabis cultivation in California we downloaded a list of all active, about to expire, and expired but pending renewal cultivation licenses from the Department of Cannabis Control's public database. Based on state regulations, licensees are allowed to cultivate a maximum area based on the type of license. (See table below.)

Cannabis Cultivation License Maximum Permitted Canopy (Area)
Specialty Cottage Outdoor Up to 25 mature plants. [2,500 sq ft]*
Specialty Cottage Indoor 500 sq ft
Specialty Cottage Mixed-Light Tier 1 and 2 2,500 sq ft
Specialty Outdoor 5,000 sq ft
Specialty Indoor 5,000 sq ft
Specialty Mixed-Light Tier 1 and 2 5,000 sq ft
Small Outdoor 10,000 sq ft
Small Indoor 10,000 sq ft
Small Mixed-Light Tier 1 and 2 10,000 sq ft
Medium Outdoor 1 acre (43,560 sq ft)
Medium Indoor 22,000 sq ft
Medium Mixed-Light Tier 1 and 2 22,000 sq ft
Nursery [21,780 sq ft]**
Processor [0 sq ft]***

Table 3: Maximum permissible canopy area depending on type of California cannabis cultivation license.

* The regulations don't specify a cap for maximum area for Specialty Cottage Outdoor cultivation; instead they limit cultivation to 25 mature plants. Based on the area of Speciality Outdoor licenses which are capped at 50 mature plants or up to 5,000 square feet of canopy, we assumed 100 sq ft per mature plant and designated a maximum canopy size of 2,500 sq ft for Specialty Cottage Outdoor licenses.

** The regulations do not define a maximum canopy size for nursery licenses, as nurseries don't grow plants to maturity. For the purposes of estimation, we are assumed a generous 1/2 acre (21,780) for each active nursery license.

*** Processor Licenses are for cultivators that only trim, cure, dry, grade, package or label cannabis. As such, we have assumed zero square feet for permitted canopy size for processor licenses.

You can view the entire spreadsheet of active cultivation licenses in California and all associated calculations of maximum possible canopy size in full detail here.

Relevant Sources

[5] California's Legal Cannabis Acreage compared to popular city parks in the State.

California's Legal Cannabis Acreage, 2,078 acres, is 0.49 times the area of Griffith Park (4,217 Acres) in Los Angeles and 2.02 times the area of Golden Gate Park (1,027 Acres) in San Francisco.

Griffith Park, Los Angeles 4,217 Acres
California's Legal Cannabis Canopy 2,078 Acres
Golden Gate Park, San Francisco 1,027 Acres

Table 4: California's Legal Cannabis Acreage compared to popular city parks in the State.

Relevant Sources:

[6] Alfalfa and Irrigated Pasture Acreage

According to the University of California, "about 1,000,000 acres of alfalfa are irrigated in California. This large acreage coupled with a long growing season make alfalfa the largest agricultural user of water, with annual water applications of 4,000,000 to 5,500,000 acre-feet." Per the California Agricultural Production and Irrigated Water Use report published by the Congressional Research Service in 2015, California irrigates over 830,000 acres of pasture.

Relevant Sources

[7] California's Almond Crop Acreage

Per California Department of Food and Agriculture's 2020 California Almond Objective Measurement Report, in 2020 California's almond acreage totaled 1.26 million bearing acres.

California has 280 state park units (including state parks, state recreation areas, state historic areas and state beaches) with an approximate area of 1.56 million acres. Of these 280 park units managed by the California Department of Parks and Recreation, 88 are officially designated as "state parks", with an area of approximately 1.16 million acres. Anza-Borrego Desert State Park, the largest state park in California, is approximately 585,930 acres.

Area (Acres)
All 280 California State Park Units 1,566,219
2020 California Almond Crop Acreage 1,260,000
California Park Units classified as "State Parks" 1,162,571
Anza-Borrego Desert State Park (Largest State Park in California) 585,930

Table 5: California's Almond Acreage Compared to Area of California's State Park System.

Relevant Sources:

[8] California's Grape Crop Acreage

Per California Department of Food and Agriculture's Grape Acreage Report, in 2020 California's grape acreage totaled 895,000 acres. Of these 895,000 acres, "wine-type grape acreage [was] estimated at 620,000 acres."

Yosemite National Park, one of California's largest and most famous National Parks, by comparison is only 759,620 acres.

Relevant Sources:

9. Total Water Usage by Crop

To calculate the total volume of water used by each crop, we simply multiply the average acre feet of water required to cultivate one acre of each crop (Figure 1) by the total area under of that crop under irrigated cultivation (Figure 2).

It is important to note that these figures are gross water use per crop. Net water use - the volume of water consumed by the crop, minus runoff and ground seepage - is often lower than the gross water used.

For reference, Shasta Reservoir is California's largest man-made lake with a gross pool storage capacity of 4,552,000 acre-feet. The city of Los Angeles with the population of nearly 4 million people used 521,915 acre feet of water in 2018.

Relevant Sources

Originally published August 25, 2021

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.