During this growing season, farmer Tommy Hanka is able to water and harvest his field of nappa cabbage near Monte Cristo Road in Edinburg.

But with growing water scarcity on both sides of the Rio Grande, Hanka said he doesn't know how long he can sustain his business.

“I hope we're not forced to sell, but the reality is we cannot farm vegetables in the Rio Grande Valley without water, without secured water,” Hanka said.

On Nov. 7, the U.S. and Mexico signed an agreement that would allow Mexico several options to repay its water debt to the U.S. as part of a 1944 water treaty between both countries.

Under the 1944 international treaty, Mexico must deliver 1,750,000 acre-feet of water to the U.S. every five years. According to the Texas Tribune, Mexico has a balance of 1.3 million acre-feet of water to fulfill in the current cycle.

READ MORE: U.S.-Mexico water agreement might bring relief to parched South Texas

The new amendment will allow Mexico to meet its delivery obligations by giving up water that was allotted to the country under the treaty.

Farmers downstream in the Rio Grande Valley and across the river in northern Tamaulipas have been plagued with water scarcity issues. 

Sonny Hinojosa with the Hidalgo County Irrigation District #2 in San Juan told Channel 5 News Mexico at least has put in writing the ways they could choose to repay the water.

“It's in place now that if Mexico wants to transfer water in storage, they now have the ability to,” Hinojosa said.

The agreement also provides options for avoiding the recurring water debt at the end of five-year water cycles.

Hanka said he thinks more work still has to be done.

The International Water and Boundary Commission says the U.S government is already in talks with Mexico to ensure they deliver water to the U.S. during the current rainy season.

Watch the video above for the full story.