New home with sewage smell
We have a new home with private septic tank. All plumbing fixtures have vents except for kitchen island which has a gravity fitting on it that is supposed to fight odors escaping through the drain. We have had our plumbers come out several times regarding sewage smell. It started in the master bath... which was remedied by a new wax seal on the toilet. Once the master was fixed the smell started in the guest bath, same story, new seal fixed the problem. Now the smell is in the laundry room, kitchen island, and worst of all the powder room. The plumber has no idea on the laundry room. The island he thinks is the gravity device that we are changing this week, as far as the powder room... its horendious!! They have changed the wax seal, and used silocone around the sink and toilet. The smell persists... usually at night. Our pipes under the sink are exposed and the wall flange does not fit snug to the wall. I have asked if this could be the problem and they say no. All sinks and drains are used regularly. Could one of the vents been punctured during construction? Also why is it so strong at night?
Please if you have any idea let me know... I'm very frustrated and our plumber seems to be clueless (they did all the rough in plumbing in the house)