For what it's worth here's his entry in the 2006 Routledge Encyclopaedia of the Blues Vol. 2 (page 1055)
WATERS, MISSISSIPPI JOHNNY
b. John Sandifer, 24 May 1935; Jackson, MS
d. 30 January 1987; Oakland, CA
Waters changed his name in honor of Muddy Waters,
a major influence as singer and guitarist. He moved to
Oakland, California, in 1956 and performed songs by
Waters, Chuck Berry, and Fats Domino. During the
1970s he performed with harmonica player Mark
Hummel and the Blues Survivors. Despite a 1983
lung operation, he continued performing as a senior
member of the Bay Area blues scene.
EDWARD KOMARA