Plumbing
Interior Design

When adding another toilet 6 feet from an existing toilet do you need a new vent and would 3-inch pipe be sufficient?

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August 18, 2005 8:59PM

where one toilet is draining to its own unshared line, the line can be 3" but once both toilets are draining to the same line, it needs to be 4". in other words, from the first toilet to the second toilet can be 3" but past the second toilet needs to be 4". there needs to be a vent downstream of the second toilet in the direction of flow if there is another fixture of any kind downstream of the two toilets.