Can I easily get a keg of plain old seltzer water somewhere?

(I’m not asking how to buy a McCann Big Mac carbonator from eBay to set up a home seltzer tap, my brother has one but I don’t need another house project 😵‍💫)

I drink a lot of seltzer water, which means I’m always running out and having to deal with all the cans. Is there somewhere in town that I can just get a keg of plain old NA carbonated seltzer water for a good price?

Sprecher has kegs of soda, so maybe would do seltzer, but their price would cost more per ounce than a 24-pack from Costco. And I don’t know that I want a lifetime supply of their flavors anyway, I’d prefer plain.

Do restaurants buy kegs of soda water or is that just all built into the soda fountains? Is there anywhere I can source this that doesn’t involve running a mini-homebrew setup in my basement?