All tanks in a camper have a vent. That way they don’t pressurize when trying to add fluid to them. The freshwater tank is always vented under the camper in case the tank is overfilled it will just simply drain onto the ground. Black and Grey tanks however have a roof vent. The reason it is on the roof is so the smell of poo from the black holding tank is up and away from where people are to help keep an enjoyable recreational experience. The vents always have a cap on them so they do not collect rainwater and fill the tanks when they are not in use. The cap that manufacturers use is just fine. Although, we have noticed that if the camper is left in storage in the hot sun while not being used or opened up over a long period of time there can sometimes be a foul smell in the camper from the black tank. Luckily, there are upgrades that can be done to help prevent this issue! Camco makes a venturi style tank vent. The idea is that as a breeze blows past it, it creates a venturi vacuum on the tank to pull odors from the tank. When the tank is in a vacuum odors can slowly or accidentally seep into the camper. The venturi is free spinning so it will always point into the breeze to create the optimal effect. Simply just remove the old vent caps and install these. Nothing else is required. Its worked very well for us throughout this past summer.
Difficulty: EASY
Tools:
#2 Square screwdriver
Phillips screwdriver
Putty knife
Small pry bar or flat screwdriver
Roof sealant