my home was built in 1976. It is out in rural area and I am on a septic system. My problem is when it rains heavily I get seweage smell inside. It can be bad. The septic has been pumped and the man said it looks good. Seems there may be a problem with my ventilation shaft. How do I address this?
If you have a seldom used drain, the p-trap could dry out and let the smell in your house, but that wouldn't have anything to do with the rain.
If heavy rain is causing the problem, then your leach field is getting saturated. The smell could be rising to the surface and drifting into your house. Other than that, the leach field could get saturated and cause the level of water in your septic tank to rise up high enough to back up a shower. One way to find out is to pull the cap on one of your cleanouts and see if you can see water/sewage in the pipe.