The Valuation Office Agency adopts the rental comparative method of valuation when valuing petrol filling stations for rating purposes. Valuations reflect the four main elements of a petrol filling station; the petrol sales forecourt, the forecourt shop, the car wash facilities and other sources of income from non-forecourt buildings such as workshops and showrooms and the like. The factors considered when making such a valuation include the fair maintainable throughputs and turnovers, which are derived from factors such as the location, layout of the site, and number of pumps.