We have a 1 1/2 yr. old home and have a suite where my son is and in the past month or so we have had a sewer like smell when he flushes toilet and uses shower. The smell is not from bathroom but closet around corner where rough in laundry is.(specifically box where taps and drain hose is located) Do you know what this could be? Or if dangerous

If the trap for the washer has dried out, it is getting sewer gas into the house. It could also be a plugged vent. Is the washer hooked up?

My question is do you run your laundry washer on a regular basis? Is there water in the trap or does the smell come out of the washer stand pipe? Can you localize the smell to a particular spot? Are there any wet areas? Back to you, Tom