It's located under the RV carriage, positioned next to the gray tank which holds the water run-off from sinks and showers. The black tank should only contain the biodegradable enzymatic product of your choice, your solid and liquid waste, and septic safe toilet paper - nothing else. Also, don't forget to clean it! Create a plan, pay attention, wear gloves, and don't get distracted. Gross things happen when we're not focused on what we're doing; the black tank fiasco scene from the movie RV with Robin Williams comes to mind. Create a plan, pay attention, wear gloves, and don't get distracted. Gross things happen when we're not focused on what we're doing; the black tank fiasco scene from the movie RV with Robin Williams comes to mind. Attach the sewer hose securely to the tank valve after removing the valve cover. Then place the clear elbow into the sewer hole. Some may screw in; some may have a rock for you to place on top of your connector. This is advisable as you don't want that line getting dislodged. Also, after a year of exploitation, I had to replace
globe valve, but I hope you will not face such a problem. I read several articles and realized that this is a very rare case when it fails.