There is no such person as "Martha Susanna Waters" in any record in colonial Virginia. (Repetition of the error on Ancestry doesn't make it true!) Middle names were extremely rare until much later. This apparently comes from combining two people.
Martha was the first wife of William Terrell (born 22 Jun 1629). They married at St. Mary's, Reading, Berks., England. No record of children or where they lived - or when Martha died. William came to America and remarried Susannah Waters and they had 10 children. Sources: Ancestry Files and LDS Records 1994
It may be possible to confirm family relationships with Susannah by comparing test results with other carriers of her mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Susannah: