I'm remodeling a bathroom in a house built in 1993 (Midwest USA). Apparently the plumbers didn't add shutoff valves under the main or master bathroom sinks... I've found plenty of instructions online for how to add a compression shutoff valve, but the plumbing under the sink goes from CPVC to copper, so I'm not sure if I should really install the fitting on the copper.
My question is; Should I install the shutoff on the copper?
Or should I use a CPVC specific shutoff and take the copper off completely?
My impression is that installing a compression fitting on the copper would be easier, but I don't know if that would be up to code in this situation.