On 9 Mar 1760 when William was 20, he married Sarah Chase (59716) , daughter of Philip Chase (49582) (ca 1713-) & Sarah Crossman, in Middletown, RI. Born on 29 Oct 1741 in Freetown, MA.317 Sarah died in Tiverton, RI bef 5 Mar 1810.

The will of Sarah Perry of Tiverton, widow of Christopher White, dated 12 Jun 1804, codicil dated 12 Aug 1804, proved 5 Mar 1810. It mentions (1) deceased son Thomas Earl, (2) daughter Phebe wife of Nathan Borden, (3) daughter Ruth wife of Elisha Brown, and (4) daugher Sarah wife of George Cook. Also mentions grandson William Earl under 21, son of deceased son Thomas Earl, and granddaugher Meribah Earl under 21, daugher of deceased son Thomas Earl; granddaughter Sarah Borden, daughter of Nathan and Phebe Borden of Tiverton; granddaughter Mary Dennis, daughter of Elisha and Ruth Brown; grandson William Earl Cook, son of George and Sarah Cook of Portsmouth. Witnesses: Parigreen White, Abigail White, Potter Cook. The codicil mentions her then husband John Perry.