Greetings and thanks in advance for any help,
I have an apartment building where the first floor sink gurgles when the upstairs sink drains. Would installing a studer valve in the upstairs line solve this?

Hi Shawn:

Most likely, installing a studor vent in the DOWNSTAIRS drain would probably help the most... if the issue is in fact due to improper venting.

Most apartment buildings that I've been in with sinks above each other are properly vented unless they added a sink AFTER initial construction and then that could lead to these issues, but again vent would go on the downstairs sink. Here, as waste from above passes by the sink downstairs without a vent the trap gets siphoned and can bubble/gurgle like you have... but I'm still doubting this as main issue.

Most likely the drain that connects both these sinks has started to clog slightly. Why do I think that? Because you mention this as it is a new issue. If venting was the issue then you would have had this gurgling issue from the very start...that make sense?

See if you can snake the drain from a cleanout in the basement if possible. If not possible then snake the drain from downstairs sink and see if that improves things. If not, then easy enough to install that studor vent under the downstairs sink later.

Be clear that if you snake the drain from downstairs sink, through the trap, the snake could go UP (drain/vent) as often as it goes DOWN the drain, so be aware of that as well as distances.

If you do install the studor vent downstairs it may also be a good time to snake the drain with a larger head on the end... just to be sure... ;)

I posted a couple pics. Of machines to use.. wear leather gloves and safety goggles and if possible when you rent the snake machine be sure it comes with a DROP HEAD attachment for the snake (see cable pic.). This drop head attachment will have a tendency to force the snake DOWN the drain more often than a snake without this head... just FYI.

Let me know what you think here...

MARK