The cellphone would not stop ringing. “Ronny, you’re 10 minutes late,” one caller whined.

But Ronny Beberman had a good reason. Having tumbled eight feet off his own seltzer truck, Mr. Beberman, 62, was answering the phone while laid out on West Seventh Street in Brooklyn, bleeding from a head gash and having broken a foot and several vertebrae. The news was also bad for his customers: Ronny the Seltzer Man would be out of service for a while.

Mr. Beberman drives the last real seltzer truck in New York, a wooden-slatted affair with crooked racks and side doors that are stuck open  the easier to strap the worn wooden cases to the side.

For nearly 40 years, he has delivered seltzer in thick, old siphon bottles to thousands of Brooklynites, each customer receiving a case of 10 every other week for $25, cash.

But on Sept. 15, just before the start of the Jewish High Holy Days, one of the busiest times of the year, Brooklyn’s Gunga Din of soda water went down, and now several hundred customers are resorting to rationing or even privation.