Below ground septic tanks can have a very distinctive and unpleasant odor. The odor comes from the vent pipes that are typically located on the roof of the house. In decentralized systems found in RV Parks there are air vent risers all around the park that allow the effluent to flow the length of the park to the treatment area. Without those vents the pipes would air lock and the effluent would not flow. Every vent is a potential source of odor, especially in hot weather. There are expensive and unsightly mechanical solutions like raising or repositioning the vent pipe or adding a charcoal filter to each vent. Cap seals on the covers only block the odor at one point. Aerobic Treatments Units are helpful but expensive to install. The most effective solution is to simply add TankTechsRx for Septic Systems to the septic system. It removes odor at the source by consuming the gasses that cause the odor. Problem solved.