This is the oldest surviving wellhead in the Old Town and was designed by Sir William Bruce and constructed by Robert Mylne in about 1675. The former was the Surveyor of the Royal Works and the latter was the King's Master Mason. The wellhead provided fresh water for the inhabitants of the Old Town prior to being supplied in houses. The water was sourced from Comiston Springs and was fed via the Castlehill Reservoir. The wellhead was restored to use again in 1997.