Unvented utility sink and washer

[SAS]

My daughter and her family move every couple of years as my son-in-law is an Army officer. I was visiting her in her new rented house, and she told me that she had problems with bad odors from the utility sink and washing machine in the basement. I took a look and both are connected to the main drain of the house just before it goes through the foundation. Each has its own P-trap, but neither is vented.

I know enough to know that this isn't good, but I have a few questions. First of all, is there really any danger to this, i.e. can the escaping sewer gas do anything other than produce an unpleasant odor? Secondly, is there something official I can have her show the owner to force him to remedy this situation? Finally, if it isn't safe and the landlord gives her the runaround, can I just add a T between the trap and the drain line and put a Studer vent in it? For the sink she could let the water drip, I suppose, but I don't have a similar solution for the washing machine. Can she just pull the hose out and get a large stopper to plug the pipe when the machine isn't in use?

 

[SAS]

So I came upon this diagram and explanation on the Inspectadia.com site. If both the utility sink and washer are within 5 feet of that waste stack, doe that mean that they don't need a separate vent? If that's true, what are my options for eliminating the sewer gas problem?

 

[Sponsor]

 

[Reach4]

That does not meet the rules. It may work in practice.

 

[Terry]

We vent everything before it enters the stack. Water from upstairs will affect the trap seals below. I would add some venting. Is sewer gas dangerous?
I guess it depends on what people are dumping in their drains nearby. It's not the best thing you can be breathing. There is a reason we have plumbing codes and inspectors for this reason.

Limits on trap arm length to the vents
1-1/2" = 42"
2" = 60"
3" = 72"