Do I need an additional vent?

[Boris Ostrovskiy]

I'm building a laundry room in the basement.
There is readily accessible plumbing that I can cut into but I don't know if I need to run an additional vent pipe leg, and if so, where do I run it?

I've made a quick, rough representation model, of current fixtures in the basement (p-traps are not pictured).
New pipe to be added is in red.
Should I cut it in before or after the vent connection for the sink?

 

[PorcelainVacation]

How long is the red pipe?

 

[Sponsor]

 

[Boris Ostrovskiy]

How long is the red pipe?

Red pipe will end up being 8-9ft

 

[Terry]

Each fixture will need a vent or an AAV for venting.

 

[Boris Ostrovskiy]

Each fixture will need a vent or an AAV for venting.

In my case, what is the best way to route the additional vent?
The existing vent is downstream from the junction, does that make it a vent for the washer, and I should add a new vent for the sink on the right side of the image?

 

[hj]

The "vent" if it is actually installed the way you drew it, is completely useless, incorrect, and illegal according to the code, so your question about WHERE to connect the new sink is irrelevant.

 

[Boris Ostrovskiy]

It wouldn't surprise me that things in that house are not up to code, I've been finding all kinds of issues.
So given the opportunity to re-do it right, how should I vent the existing sink, and the new washing machine drain?

 

[Terry]

Starting from the fixture, you have a p-trap, and then a vent. The vent could be an AAV if you can't run a pipe up through the roof, or tie back in to an existing vent at 6" above the flooding level of any connected fixture that it vents. On the same floor that is typically 42" as most counters are 36" at the highest.