The world number one, 32, beat Waters 11-2 11-5 11-4 in just 24 minutes at the National Squash Centre to secure a first national title since 2012.
"I am really happy that I played well all week to win the title again," she told the tournament website.
In the men's event, Nick Matthew beat James Willstrop 11-2 6-11 11-3 11-3 to win his eighth British title.
World number three Matthew, 35, lost his first set of the week but recovered to win the final in 50 minutes.
Laura Massaro won her third British title with a straight-set final victory over Alison Waters in Manchester.