Louisiana has a total land and water area of over 52,000 square miles (U.S. Census Bureau, 2012), and water resources are abundant throughout the State. Every day, large amounts of groundwater and surface water are withdrawn from natural sources and are used for public-supply, industrial, power-generation, rural-domestic, livestock, irrigation, and aquaculture purposes. Water-use data are essential to appraise the effects of present use and to plan for the future use of Louisiana’s water resources. The U.S. Geological Survey (USGS), in cooperation with the Louisiana Department of Transportation and Development, has collected and published water-withdrawal and water-use information on a 5-year basis since 1960.

Water-withdrawal information for public-supply, industrial, and power-generation facilities was primarily obtained directly from the facilities. The main source for public water system information was the Louisiana Department of Health’s Safe Drinking Water Program, Drinking Water Watch database (Louisiana Department of Health, 2020) and the U.S. Environmental Protection Agency’s Safe Drinking Water Information System (U.S. Environmental Protection Agency, 2020). These sources provided contact information, identified whether the water source was groundwater or surface water, and indicated the current operational status (active or inactive) for all the current water suppliers in a parish. The Louisiana Manufacturing Industry Database (Manufacturers’ News, Inc., 2020), an online directory that lists Louisiana manufacturers and their contact information, was the main source for industrial facilities, and the U.S. Energy Information Administration (U.S. Energy Information Administration, 2021), along with prior information acquired during previous compilations, provided the majority of the information for power-generation facilities. Hydroelectric power-generation instream water use was not included in surface-water withdrawals in this report because the water was not considered withdrawn but is discussed in the “Power Generation” subsection of “Water Use by Category.” A master list of these water-use facilities was compiled into a local database at the USGS office in Baton Rouge, La.

Water withdrawals for rural-domestic and livestock uses were estimated on the basis of population data and per capita use rates. Population data were compiled from multiple sources. Parish and State population estimates for 2020 were obtained from the U.S. Census Bureau (2020) and rural-domestic populations for each parish were based on U.S. Census Bureau’s American Housing Survey (U.S. Census Bureau, 1993, 2011), which reported estimates of populations served by a public-supply facility. For the purpose of this report, an average of 80 gallons per day (gal/d) per person was used to estimate withdrawals by the rural-domestic portion of the population (Lurry, 1987). Population data used for livestock estimates were from the Louisiana Cooperative Extension Service (2023). In Louisiana, livestock that require substantial amounts of water included cattle, horses, swine, sheep, and poultry. For consistency and comparability with past water-use reports, the per capita use rates for livestock from previous reports were used to estimate withdrawals for livestock. The rates used (in gal/d per head) were as follows: milk cows, 20; other cattle, 10; horses, 10; swine, 3.0; sheep, 2.0; and poultry, 0.04 (Lovelace and Johnson, 1996, p. 11).

Water withdrawals for irrigation were estimated on the basis of crop acreage in each parish and irrigation application rates. Several different sources were used to study and develop estimates of water application-rate data for crop irrigation. The sources included the U.S. Department of Agriculture's 2017 Census of Agriculture and 2018 Irrigation and Water Management Survey (National Agricultural Statistics Service, 2019a, b) in addition to the Louisiana State University Agricultural Extension. All crop-acreage data originated from inventories compiled by the Louisiana Cooperative Extension Service (2023) for calendar year 2020.

Water withdrawals for aquaculture were estimated on the basis of reported and estimated use. Water withdrawals at bait farms and fish hatcheries were obtained directly from the facilities. Water withdrawals for crawfish, catfish, and alligator farms were estimated for each parish using 2020 acreage or other production data available from the Louisiana Cooperative Extension Service (2023) and application rates for crawfish and catfish were obtained from the Louisiana State University Agricultural Extension Service.

Water-use information was compiled and divided into two groups: site-specific and aggregate. The information for public-supply, industrial, and power-generation facilities was collected for specific sites; that is, the location of the facility and its water sources were known and recorded with the withdrawal data. The information for rural-domestic, livestock, irrigation, and aquaculture withdrawals was estimated parish-wide, without knowledge of the exact location of each user or source of water. For these parish-wide, aggregated withdrawals, per capita use rates were used to estimate withdrawals for livestock and aquaculture, and water was distributed on the basis of data reported by farmers and county agents. Louisiana water-well registration inventories provided by the Louisiana Department of Natural Resources include data on the distribution of irrigation wells screened in different aquifers within a parish (Louisiana Department of Natural Resources, 2020). This information was used to distribute aggregated groundwater withdrawal data among the appropriate aquifers. Aggregated surface-water withdrawals in each parish were distributed among hydrologic basins on the basis of the percentage of the parish within each basin. Seasonal withdrawals, such as for irrigation and sugar cane processing, were prorated for the entire year.

All the water-use information was entered into a database at the USGS office in Baton Rouge, La. All withdrawal data in this report were retrieved from the USGS database and are expressed in millions of gallons per day (Mgal/d). The withdrawal data used in this report are available online in an associated U.S. Geological Survey data release (Robinson, 2025).

Most of the uses of water described in this report require freshwater, which, for purposes of this report, is defined as water containing less than 1,000 milligrams per liter (mg/L) of dissolved solids, or, for drinking water, less than 250 mg/L of chloride (U.S. Environmental Protection Agency, 2024). Most of the water withdrawals described in this report were assumed to be fresh. However, in some areas of Louisiana, especially near the Gulf of Mexico, USGS historical data indicate that chloride concentrations could exceed 250 mg/L, indicating a presence of saline water (Tollett and others, 2003; Lovelace, 2007). Collection and presentation of chloride concentrations in water withdrawn was beyond the scope of this study.

Water use is defined in this report as water withdrawn or diverted from a groundwater or surface-water source to be used for public-supply, industrial, power-generation, rural-domestic, livestock, irrigation, or aquaculture purposes. The glossary at the end of this report offers further explanation of the water-use categories that are discussed in this section.

In 2020, withdrawals for power generation accounted for about 47 percent of the total water withdrawn from both groundwater and surface-water sources, industry accounted for 24 percent, irrigation (rice and general irrigation combined) 14 percent, public supply 8.3 percent, aquaculture 6.8 percent, and rural domestic and livestock combined accounted for the approximated remainder of 0.53 percent (fig. 5). Irrigation accounted for the greatest percentage of groundwater withdrawals, about 43 percent of the total (fig. 6), and power generation was the category with the greatest surface-water withdrawals in the State, accounting for about 59 percent of the total withdrawals from all surface-water sources (fig. 7).

Total withdrawals from groundwater and surface-water sources in 2020 were approximately 8,700 Mgal/d (table 10). Of this total, about 1,900 Mgal/d was from groundwater and about 6,800 Mgal/d was from surface water. St. Charles Parish had the greatest total withdrawals, at about 2,500 Mgal/d (figs. 17, 18). Acadia Parish had the greatest groundwater withdrawals in the State, at about 210 Mgal/d (fig. 19). In addition to having the greatest total withdrawals, St. Charles was also the parish with the greatest surface-water withdrawals in the State, at about 2,400 Mgal/d (fig. 20). About 51 percent (960 Mgal/d) of all groundwater was withdrawn from the Chicot aquifer system, and about 24 percent (450 Mgal/d) was withdrawn from the Mississippi River alluvial aquifer (table 7). About 72 percent (or 4,900 Mgal/d) of all surface water withdrawn in Louisiana was withdrawn from the Mississippi River main stem (table 6).

Since 1960, Louisiana’s population has increased by 43 percent, but from 2015 to 2020, the State’s population decreased by 0.28 percent (fig. 23) (U.S. Census Bureau, 1961, 2016, 2020). Since 2015, Calcasieu, St. Tammany, East Baton Rouge, Ascension, and Jefferson Parishes had the largest increases in population and Caddo, Orleans, Acadia. Terrebonne, and Iberia Parishes had the largest decreases in population.

Total public-supply withdrawals increased by approximately 1.4 percent from 2015 to 2020 (fig. 24), comparable to the increase in population. The total groundwater withdrawals for public supply decreased by 0.23 percent and surface-water withdrawals increased by 3.0 percent. Public-supply withdrawals decreased in 33 of Louisiana’s 64 parishes between 2015 and 2020. The median change in public-supply withdrawals by parish was a decrease of 0.01 Mgal/d; that is, the change for half of the parishes was greater than a 0.01 Mgal/d increase, and the change for the other half was less than the 0.01 Mgal/d increase. East Baton Rouge Parish had the greatest decrease, at 3.3 Mgal/d, and St. John the Baptist Parish had the greatest increase in total public-supply withdrawals, at 5.2 Mgal/d. Since 1960, public-supply withdrawals have increased by 170 percent.

Total industrial withdrawals decreased by 2.3 percent from 2015 to 2020 (fig. 25). Industrial withdrawals from groundwater sources decreased by 14 percent and industrial withdrawals from surface-water sources decreased by 0.76 percent. From 2015 to 2020, 30 of the 54 parishes (56 percent) that had water withdrawals for industrial purposes had a decrease in withdrawals and the median difference in withdrawals during this period was a decrease of 0.01 Mgal/d. Calcasieu Parish had the greatest decrease, at 40 Mgal/d, whereas Iberville Parish had the greatest increase, at 72 Mgal/d. Since 1960, total industrial withdrawals in Louisiana have decreased by 49 percent.

Groundwater withdrawals for power generation decreased by 18 percent from 2015 to 2020 and surface-water withdrawals decreased by 4.8 percent, resulting in an overall decrease of 4.9 percent for power-generation withdrawals from 2015 to 2020 (fig. 26). Between 2015 and 2020, 9 of the 16 parishes (56 percent) that had water withdrawals for power generation showed a decrease in withdrawals, and the median change in withdrawals for the parishes that generated power was a decrease of 0.31 Mgal/d. The parish with the greatest decrease in withdrawals was Orleans Parish, at 270 Mgal/d, and St. Charles Parish had the greatest increase, at 82 Mgal/d. The decrease in power-generation withdrawals from 2015 to 2020 is likely due to the decommission and deactivation of two powerplants in Iberville and Orleans Parishes. Total withdrawals for power generation in Louisiana have increased by 81 percent since power-generation withdrawals were first reported in the 1965 water-use report (fig. 26).

Rural-domestic withdrawals in Louisiana decreased by 1.2 percent from 2015 to 2020 (fig. 27). Thirty-nine of the 64 parishes (61 percent) had a decrease in rural-domestic water use from 2015 to 2020, and the median change in water withdrawals for rural-domestic use was a decrease of less than 0.01 Mgal/d. Vermilion Parish had the greatest decrease, at 0.20 Mgal/d, and Vernon Parish had the greatest increase, at 0.095 Mgal/d. The small decrease in total rural-domestic withdrawals from 2015 to 2020 is consistent with, and may be due in part to, the continued expansion of public suppliers into rural areas and a subsequent shift from the use of private domestic wells to public supplies. Since 1960, groundwater withdrawals for rural-domestic use have decreased by 4.4 percent (fig. 27).

Groundwater withdrawals for livestock increased by 16 percent, surface-water withdrawals increased by 5.2 percent, and total withdrawals for livestock increased by 11 percent from 2015 to 2020 (fig. 28). Despite the increase in total withdrawals for livestock, 34 of 64 parishes (53 percent) that had water withdrawals for livestock had a decrease from 2015 to 2020 and the median change was a decrease of 0.01 Mgal/d. Sabine Parish had the greatest decrease, at 0.081 Mgal/d, and Beauregard Parish had the greatest increase, at 0.12 Mgal/d. Withdrawals for livestock in Louisiana have decreased by 73 percent since 1960 (fig. 28).

From 2015 to 2020, total withdrawals for rice irrigation increased by 13 percent, congruent with a 13-percent increase in rice-harvest acreage (Louisiana Cooperative Extension Service, 2017, 2023). Groundwater withdrawals for rice irrigation increased by 13 percent, and for the same period, surface-water withdrawals for rice irrigation increased by 12 percent (fig. 29). From 2015 to 2020, water withdrawals increased in 18 of the 30 parishes (60 percent) that had water withdrawals for rice irrigation, and the median change in withdrawals for these parishes was an increase of 1.9 Mgal/d. Morehouse Parish had the greatest increase, at 36 Mgal/d, and Calcasieu Parish had the greatest decrease, at 8.3 Mgal/d. Total withdrawals for rice irrigation in Louisiana have decreased by 3.4 percent from 1960 to 2020 (fig. 29).

Total withdrawals for general irrigation increased by 12 percent from 2015 to 2020. During the same period, groundwater withdrawals for general irrigation increased by 14 percent, and surface-water withdrawals increased by 7.5 percent (fig. 30). From 2015 to 2020, water withdrawals decreased in 35 of the 62 parishes in Louisiana (56 percent) that had general-irrigation withdrawals, and the median change in general-irrigation water use was a decrease of less than 0.01 Mgal/d. Pointe Coupee Parish had the greatest decrease, at 2.4 Mgal/d, and Franklin Parish had the greatest increase, at 11 Mgal/d. General-irrigation withdrawals in Louisiana have increased by 820 percent since 1960 (fig. 30).

From 2015 to 2020, total withdrawals for aquaculture in Louisiana increased by 20 percent (fig. 31). During the same period, groundwater withdrawals increased by 21 percent, and surface-water withdrawals increased by 16 percent. From 2015 to 2020, withdrawals decreased in 21 of the 36 parishes (58 percent) that had aquaculture withdrawals, and the median change in aquaculture withdrawals for these parishes was a decrease of 0.01 Mgal/d. Vermilion Parish had the greatest increase, at 64 Mgal/d, and Acadia Parish had the greatest decrease, at 15 Mgal/d. Total withdrawals for aquaculture in Louisiana have increased by 290 percent since aquaculture withdrawals were first reported in the 1980 water-use report (fig. 31).

Total groundwater withdrawals for all water-use categories increased by 130 Mgal/d (7.1 percent) from 2015 to 2020 (fig. 32). Since 2015, withdrawals from the Chicot aquifer system increased by 13 percent, and withdrawals from the Mississippi River alluvial aquifer increased by 18 percent. Total surface-water withdrawals decreased by 2.1 percent from 2015 to 2020 (fig. 33). The Mississippi River main stem had the greatest withdrawals of any surface-water basin in 2020, at 4,900 Mgal/d, or 72 percent of all surface water, and it had a decrease of just 1.1 percent from 2015.

Figure 34 shows increases and decreases in total water withdrawals in Louisiana since 1960. Withdrawals of both groundwater and surface water increased steadily from 1960 to 1980. For that period, total groundwater withdrawals increased by approximately 73 percent (from 1,000 to 1,800 Mgal/d), total surface-water withdrawals increased by 150 percent (from 4,400 to 11,000 Mgal/d), and total water withdrawals in Louisiana increased by approximately 130 percent (from 5,400 to 13,000 Mgal/d). From 1980 to 2020, total groundwater withdrawals increased by 5.3 percent (about 94 Mgal/d), total surface-water withdrawals decreased by 37 percent (about 3,900 Mgal/d), and total water withdrawals decreased by 31 percent (about 3,800 Mgal/d). As indicated in figure 34, from 2015 to 2020, total water withdrawals in Louisiana decreased by 0.22 percent.

Overall, since 1960, groundwater withdrawals have increased by 83 percent, surface-water withdrawals have increased by 56 percent, and total water withdrawals have increased by 61 percent. Figure 35 summarizes withdrawals from 1960 to 2020, showing total withdrawals along with total withdrawals by category for the same period.

The U.S. Geological Survey (USGS), in cooperation with the Louisiana Department of Transportation and Development, collected water-withdrawal and water-use data from a 2020 inventory of water withdrawals in Louisiana. In 2020, public water suppliers in Louisiana withdrew approximately 720 million gallons per day (Mgal/d) of water, 360 Mgal/d from groundwater sources and 370 Mgal/d from surface-water sources, to supply approximately 4.2 million Louisiana residents. From 2015 to 2020, groundwater withdrawals for public-supply use decreased by 0.23 percent, surface-water withdrawals increased by 3.0 percent, and total water withdrawals for public-supply use increased by 1.4 percent.

Industry in Louisiana withdrew approximately 2,100 Mgal/d of water, 220 Mgal/d from groundwater sources and 1,900 Mgal/d from surface-water sources. Industrial withdrawals in 2020 accounted for 24 percent of all withdrawals. Since 2015, industrial groundwater use decreased by 14 percent and surface-water use decreased by 0.76 percent, resulting in an overall decrease of 2.4 percent in withdrawals.

Power-generation facilities withdrew approximately 4,100 Mgal/d, which accounted for about 47 percent of all water withdrawn in 2020. Of the 4,100 Mgal/d, only 31 Mgal/d came from groundwater sources, whereas more than 99 percent (more than 4,000 Mgal/d) originated from surface-water sources. The Mississippi River provided 73 percent (2,900 Mgal/d) of the surface water withdrawn for power-generation use. Groundwater withdrawals for power generation decreased by 18 percent from 2015 to 2020. Surface-water withdrawals decreased by 4.8 percent, resulting in an overall decrease of 4.9 percent for power-generation withdrawals from 2015 to 2020.

In 2020, an average of 69,000 Mgal/d of Mississippi River water passed through the turbines of the hydroelectric powerplant at the Old River Control Structure in southern Concordia Parish. For the hydroelectric powerplant at the Toledo Bend Reservoir in Sabine Parish near Burkeville, Texas, an average of 3,700 Mgal/d of water passed through its turbines, 1,900 Mgal/d of which was counted as power-generation instream use for Louisiana in 2020. Hydroelectric power-generation instream use was not included in surface-water withdrawals in this report because the water was not considered to be withdrawn.

Approximately 490,000 people, or about 10 percent of Louisiana’s total population, using privately owned domestic wells, withdrew an estimated 39 Mgal/d of groundwater for domestic use in 2020. Rural-domestic withdrawals decreased by 1.2 percent from 2015 to 2020. The small decrease is consistent with the continued expansion of public suppliers into rural areas and the resultant shift from the use of private domestic wells to public supplies.

Withdrawals for livestock were approximately 7.0 Mgal/d of water in 2020. Of this total, 3.7 Mgal/d was groundwater and 3.3 Mgal/d was surface water. Groundwater used for livestock increased by 16 percent and surface water increased by 5.2 percent, with a total increase of 11 percent in withdrawals for livestock from 2015 to 2020.

Rice farmers withdrew approximately 930 Mgal/d of water to irrigate their fields in 2020. Of this total, 620 Mgal/d was groundwater and 310 Mgal/d was surface water. The Chicot aquifer system in southwestern Louisiana provided 71 percent of the groundwater used for rice irrigation. Groundwater withdrawals for rice irrigation increased by 13 percent and surface-water withdrawals increased by 12 percent from 2015 to 2020. Rice-harvest acreage increased by 13 percent, and, congruently, total withdrawals for rice irrigation increased by 13 percent.

Farmers also withdrew approximately 190 Mgal/d of groundwater and 60 Mgal/d of surface water to irrigate crops other than rice in 2020. Groundwater withdrawals for these crops increased by 14 percent and surface-water withdrawals increased by 7.5 percent from 2015 to 2020. Withdrawals for general irrigation totaled about 250 Mgal/d in 2020 and increased by 12 percent from 2015 to 2020.

Water withdrawn for aquaculture in Louisiana was approximately 590 Mgal/d in 2020. Of this total, 410 Mgal/d was groundwater and 180 Mgal/d was surface water. Since 2015, groundwater withdrawals have increased by 21 percent and surface-water withdrawals have increased by 16 percent. Total withdrawals for aquaculture increased by 20 percent from 2015 to 2020.

Total withdrawals in 2020 were approximately 8,700 Mgal/d. Total groundwater withdrawals were 1,900 Mgal/d, and total surface-water withdrawals were 6,800 Mgal/d. In 2020, about 51 percent (960 Mgal/d) of all groundwater withdrawn was from the Chicot aquifer system, and about 24 percent (450 Mgal/d) was withdrawn from the Mississippi River alluvial aquifer. Approximately 72 percent (4,900 Mgal/d) of all surface water withdrawn was from the Mississippi River main stem.

From 2015 to 2020, groundwater withdrawals from the Chicot aquifer system increased by 13 percent, and withdrawals from the Mississippi River alluvial aquifer increased by 18 percent, resulting in a 7.1-percent increase in total groundwater withdrawals. During the same period, there was a 1.1-percent decrease in surface-water withdrawals from the main stem of the Mississippi River and total surface-water withdrawals decreased by 2.1 percent. Since 2015, total withdrawals for all water-use categories decreased by just 0.22 percent.

All water-withdrawal and water-use data presented in this report should be considered estimates. Because of rounding, totals and percentages presented in the tables, figures, and text in the report may differ slightly from totals or percentages calculated individually.