Waterson weighed in at 115 pounds and Hill was 115.5. The two will meet in the UFC Fight Night headliner Saturday at the UFC Apex in Las Vegas.
Hill is the first Black American woman to headline a UFC card.
Waterson (17-8) has dropped two straight and will be looking to return to divisional contention Saturday. The New Mexico resident was on a three-fight winning streak prior to this skid. Waterson, 34, is ranked No. 7 at strawweight by ESPN.
Hill (12-8) is one of the UFC's most active fighters. The San Diego resident has fought three times already this year. Her February bout against Loma Lookboonmee was her sixth fight in 337 days, a UFC record in that span of time. Hill has the most fights in UFC strawweight history (15).
Hill, 35, is coming off a close split-decision loss to Claudia Gadelha in May. She was on a three-fight winning streak before that.
The UFC had three fights changed officially Friday morning.
Frank Camacho tested positive for COVID-19 this week and was removed from a fight against Brok Weaver. Jalin Turner will step in and fight Weaver at a 165-pound catchweight. Kevin Croom will now fight Roosevelt Roberts in a lightweight bout. Roberts' initial opponent Matt Frevola withdrew due to injury.
A scheduled flyweight bout between Matt Schnell and Tyson Nam is off Saturday's UFC Fight Night card after Schnell collapsed while cutting weight Friday morning and was taken to the hospital, his manager Matt Weibel wrote on Twitter.