I live in a ranch with a basement ready to be finished except we have a stench we can not get rid of. Our home is built(as is the whole neighborhood)on what used to be a clay pit. We are the only house in our neighborhood with a an issue of a sewer like smell that has now penetrated our main living floor in every room.

In the basement we can have an area cutout of the basement floor foundation that directly accesses the drain pipe used for the stormdrains to the street. This pipe is capped (some of our neighbors leave theirs uncapped but when we did this, the smell was even worse). We have installed a sump pump to remove some of the high water level that ideally should flow down that pippe but the ground water level is still present whether or not the cap is on the drainage pipe so we keep it capped. We have had numeous plumbers as well as the Town Public Works dept out to look at it but but no one will give us any help as to how to fix this problem or why after 5 years it is suddenly an issue. Any suggestions are greatly appreciated.