Just replaced the toilet in my master bath, and it had a 4" pipe all the way to the toilet. Barely got the wax seal to fit. Someone wanted it to drain, I guess. The pipe had been replaced sometime, as it's plastic, with the old cast iron pipe still in place a couple feet away(the house was built in 1920).

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past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)