I'm extending a water pipe to enable me to replace/install a new stop tap in the adjoining garage. The house was built circa 1975 and I've discovered that the incoming supply pipe measures approx 21.6 mm and is a of black plastic material - initially, I thought the pipe would be of 20mm diametre and was going to cut the pipe and extend using the MDPE fixings and 20 mm pipe.

My concern is this:
Will the existing pipe accept the 20mm female MDPE push fit coupler (inc. ancillary components)? - If not, is there an alternative method?

Thanks Dave

What country are you from?
All our measures are ID (inside diameter).
Our pipes run;
1/2" = 12.7mm
3/4" = 19.05m
1" = 25.4mm
Can you convert To Inside Dimension in inches and repost your question? Cheers, Tom