What size water hosing is used? Andrzej August 04, 2017 13:02 Updated Follow We use 8mm internal diameter hosing (around 10mm external) for all of our water lines. Related articles Why are your prices higher than competitors? Do I have to protect the HOTTAP from the elements? Where is Joolca based? Setting up your HOTTAP How long is the warranty period for? Comments 0 comments Please sign in to leave a comment.