We had a new septic system put in with extensive leach field, since then whenever we shower, run dishwasher or W&D, a sewer smell surrounds the outside of the house. We had the vent pipes extended, but it made no difference. The only time we had relief was when one of the pipes leading to the septic disconnected and sewage was flowing freely under and above ground. What's our problem? We've had it pumped, but that had no impact.