Lead pipes inside houses were used for all homes, up into the 30s, except I guess the odd mansion that might have had copper (and maybe iron for heating).
Copper pipes was the replacement of lead pipes.
Some homes had iron mains pipes, which I always think of as strange.
Copper pipe was used in the 40s and beyond, but some new lead pipes were still being installed in the 50s and probably 60s.
My house is 1950s and was all copper, including underground copper mains, which is still in use, but 1/2" beyond boundary was originally all lead, until modernised