I would like to place a laundry sink in the basement. The location in question is under the kitchen. I can tie into the drain pipe from the kitchen which would run vertically, right next to the laundry sink. However, the nearest point where I could attach a vent line is about twenty feet from the kitchen drain. My question is whether this twenty foot horizontal length of vent line too long to work properly?

To answer your question no. There is no limit on the length of a vent either horizontal or vertical. Good luck, Tom

Even though there is no limit to how long the vent runs horizonal there can be a problem if your drain for the washer becomes partiality clogged debris can be pushed back up into the vent line until it can become completely clogged itself.

Even though there is no limit to how long the vent runs horizonal there can be a problem if your drain for the washer becomes partiality clogged debris can be pushed back up into the vent line until it can become completely clogged itself.


While I hate to disagree with letmetellu it is highly unlikely, since if the washer drain became clogged the first place "debris" will spill out would be the lowest point which is the washer stand pipe. The backup would never reach the vent. My answer still stands; "To answer your question no. There is no limit on the length of a vent either horizontal or vertical."
Run the vent. Regards, Tom