By the 1730s Lowther was reputed to be the richest commoner in England, enjoying an income of about £25,000 a year at his death. He was a Governor of St Thomas' Hospital and a founding Governor of the Foundling Hospital, and the principal contributor to the construction and endowment of two new churches in Whitehaven. His own lifestyle was frugal, which earned him a reputation for parsimony and the soubriquet of "Farthing Jemmy", After his death, anecdotes appeared suggesting him to be both penny-wise: