Summary: Emergency units responded to reports of an inside gas leak at 3800 Derby Court, near the intersection with Delano Drive, in Manassas, Virginia. Multiple fire and rescue units were dispatched to the scene. Upon arrival, responders detected a smell of gas inside the residence, advised evacuation, and began investigating the source. Initial meter readings were normal, and further checks indicated the likely source was sewer gas rather than a hazardous leak. The incident was determined to be of good intent, and all units were released with no danger to the public.