That's for 3+ floors only here. The 8' rule.2" is more then plenty in my book, I agree about sudsing, but there is a regulation for that, tie in's cannot be any closer then 8', when coming down from a second floor. verticle to horizontal, UPC
I think 3" is a waste in my book, the washer pumps out alot of water, but with 3", will lose it's self scouring principals.
just my 2 cents :thumbsup: