I want to know the use scenario of both, I have a 40 mm drain pipe in the ground and 40 mm shower trap pipe so I want to connect them both. I guess for my use scenario it might not matter much due to low pressure, however that raised the question if I should nearly always choose compression instead of push-fits?

Also why do compression joints sometimes come with the additional hard/flat washer along side the coned rubber one, sometimes they don't?

1 Answer 1


(this answer has a UK perspective)

As I understand it the main advantage of compression waste fittings is that they are not too fussy about the exact size and material of the pipe. This means they can be used with both the pipe designed for solvent-weld fittings and the pipe designed for pushfit fittings. They also have more wiggle room during assembly which is handy when trying to insert a new fitting into an existing pipe run.

The downside is they are bulkier and cost more than push fit fittings.

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