As Forecourt Trader revealed exclusively last summer Costco won planning permission for a PFS in the car park of its Liverpool site.
Nick Deeks, Costco UK's director of real estate, told Forecourt Trader: "We are now working with contractors who we hope will start work on site shortly. We anticipate that the building programme will be in the order of 10 weeks."
The plans are for a PFS providing 16 fill positions, which would only sell fuel to Costco members.
Costco is a major player in the north American market with a worldwide turnover across all its product ranges of $100bn, and customers voted it north America's favourite petrol station operator, according to US customer intelligence company Market Force.
Costco prides itself on selling merchandise at "substantially lower prices than are typically found at conventional wholesale or retail outlets", and Market Force said the low prices and convenient petrol pumps in north America were winning market share from other operators.
Deeks said it was too early to announce plans for the other 24 UK sites which stretch from Aberdeen in the north to Cardiff in Wales and south to Southampton, but Costco was refused planning permission for a PFS at its Thurrock site due to environmental issues.