Depends on flow levels. It will operate just like a "durso" standpipe. The tube sticking out creates an open air vent so that as the water speeds up it wont create a siphon and rapidly drain creating allot of noise. But it keeps it from being as loud because the small air vent baffles allot (not all) of the noise coming from the water draining down the pipe. The deal is it won't be loud if you can keep the flow low enough that the water adheres to the pipe walls. If it starts to churn and create vertices in the middle of the pipe as it goes down it will create the gurgling noise. I have no idea what that flow level would be. I think for a 1 inch pipe it probably wont be more that 300 or so. But don't hold me to it. That is just a very uneducated hearsay guess. I have no direct experience running a durso.