I am moving the location of our washing machine to another room. I am going to connect the drain into the same system but it will be farther away from the original drain. Do I need to run a new vent stack up throught the roof or will the old vent allow the water to drain properly.
Sorry, but "another room" does not give enough information. There are also local codes that may be affected. The distance from the drainline is what determines what needs to be done. A vent is still required on all fixtures. Not having a vent will cause the trap water to be sucked out and allow sewer gas into the house. You should not need to run the vent through the roof unless the washer is going to be quite a distance from other fixtures already in the area.
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