The agrochemical company formerly known as Monsanto has in recent years remained among Maui County’s top water customers, using millions of gallons more per year than major resorts and residential developments, county data shows.

While the genetically modified seed industry has overall declined across the state, information provided by the Department of Water Supply in response to a public records request shows that two Kīhei farms run by Monsanto — now owned by the pharmaceutical and agroscience company Bayer — have increased their water consumption on Maui by about 13% since 2021.

In 2024, those two properties each used more water than all but two of the department’s other customers, according to county data. That year, the two agricultural parcels, which total about 600 acres, were billed for a combined 122.9 million gallons of water, up from 118.7 million in 2023, 102.6 million in 2022 and 108.4 million in 2021, county records show. 

Other top water customers include the real estate investment fund that owns the Grand Wailea Resort, the limited liability company that owns the Hotel Wailea, and the Ho’olei Association of Apartment Owners, which in 2024 were billed for approximately 88.3 million, 68.9 million and 47.2 million gallons of water, respectively. 

Bayer, which also operates farms on Moloka‘i and O‘ahu, plays a prominent role in Hawaiʻi’s genetically modified seed industry. The company develops genetically engineered seeds — predominantly corn — to improve crop tolerance to drought, disease and pests. Bayer also acquired Roundup, developed by Monsanto, a weed-killer that has been the center of thousands of lawsuits over concerns it causes cancer.

Monica Ivey Smith, a spokeswoman for Bayer, said the company “has a longstanding commitment to being a good steward of natural resources, including water,” across its Hawai‘i operations, and each of its farms has a soil and water conservation plan developed in collaboration with the U.S. Department of Agriculture’s Natural Resources Conservation Service.

“Across all our farms, we continue to look for opportunities to improve our soil and water conservation practices as part of our broader commitment to sustainable agriculture and responsible stewardship of Hawaii’s natural resources,” Smith said in a statement Tuesday.

Bayer has adopted land management practices including the use of “precision irrigation methods,” such as drip irrigation and sensor-based feedback systems, to minimize its water consumption by delivering water directly to the plant root, Smith added.

In a statement Tuesday, a county spokesperson said officials were unable to comment on the company’s water usage and could only provide data.

Lucienne de Naie, who steers the Sierra Club’s Maui Group, said Monsanto long used “a tremendous amount of water” that could go to better community uses.

“We have to say, ‘Does their crop fit our water budget?’” she said. “There is no really good justification for using potable water that could go to homes and could go to affordable housing.”

The amount of groundwater used for agricultural purposes on Maui has increased steadily over the past five years, with more than 13 million gallons flowing to agricultural uses across the county every day, according to a state dashboard. De Naie said this is likely in part due to drier conditions.

Most of Maui has been facing a water shortage due to drought this summer, with restrictions on water usage for West, Upcountry, South and Central Maui.

The total gallons pumped from wells on Maui for agricultural purposes increased more than 12-fold between 2019 and 2024, according to data from the state Commission on Water Resource Management. Agriculture consumed more than 3.7 billion gallons of groundwater in 2024 – about twice as much as all the island’s golf courses combined, according to CWRM data. 

A Fraught History

Agricultural technology companies have long viewed Hawaiʻi’s tropical climate and year-round growing season as beneficial for their efforts to develop new varieties of seeds, but some residents have been extremely critical of their pesticide usage and have attempted to place new restrictions on their operations.

The company pleaded guilty in 2020 to environmental crimes related to its use of a banned pesticide known as Penncap-M on seed corn at Valley Farm on Maui in 2014, despite having been made aware that the substance had been prohibited by the U.S. Environmental Protection Agency the year prior. 

Monsanto was also charged in 2019 with two felony offenses for storing Penncap-M at locations on Maui and Molokaʻi after the company was supposed to have disposed of the chemical, according to court documents. Monsanto signed a deferred prosecution agreement, but the company later violated that agreement when it was charged with unlawful use of a different pesticide on Oʻahu. 

In addition to receiving three years of probation and being required to submit to an independent audit every six months for three years, Monsanto was ordered to pay more than $12 million in criminal fines as well as $10 million in community service payments to several state agencies, including the Department of Agriculture and the Department of Land and Natural Resources.

Civil Beat’s coverage of Maui County is supported in part by a grant from the Nuestro Futuro Foundation. Civil Beat’s coverage of environmental issues on Maui is supported by grants from the Center for Disaster Philanthropy and the Hawai‘i Wildfires Recovery Fund and the Doris Duke Foundation.