Pipes and hoses

Most hot tubs are manufactured with pipework in imperial sizes, with names in inches. The name of the pipe does not correspond to the actual size in inches! We know... it's confusing. Below are the inside diameters of the different female fittings that are commonly found in spas and hot tubs. These sizes correspond to the outside diameter of the pipe, of course.

• 1/4 inch: 9 mm
• 3/8 inch: 14 mm
• 1/2 inch: 21 mm (adapter to 20 mm available)
• 3/4 inch: 27 mm (adapter to 25 mm available)
• 1 inch: 33 mm (adapter to 32 mm available)
• 1.5 inches: 48 mm (adapter to 50 mm available)
• 2 inches: 60 mm (adapter to 63 mm available)
• 2.5 inches: 73 mm