Q: We installed a toilet inside our cottage, and since then there is a sewage smell out-side that seems to be coming from our vent stack. There are lots of trees and a large hill right behind our cottage. What is the best way to solve this problem?—Sinclair Robinson, via email
A: That will depend on what’s causing the problem. You mention the trees and a big hill, which suggests that you think that they’re playing a role.
Good instincts: “If the new toilet included a new vent, then an odour is possible because of airflow downdraft from the topography and the tree cover,” says Sandy Bos, an inspector with the Township of Muskoka Lakes. If the objects around the cottage are taller than the vent pipe, negative pressure can pull the septic gas exiting the vent back down to settle around your cottage. Extending the vent stack could help, says Bos.
On the other hand, the smell may have nothing to do with new plumbing or trees or hills. A
