I think those fittings are rated at 100 PSI which is (approximately) that of a 'normal' house. The marble locks inside pretty snugly but it could potentially cause micro-fractures in the plastic over time. I have only tested it on a low pressure gravity system and a small hydraulic ram pump that I built...so I am not sure about the viability of it on a high pressure system because the hydraulic ram pump was (I am guessing here) maybe producing 25-30 PSI so I am hesitant to say yes.