In part 1, part 2, part 3 and part 4 of this series of posts I’ve discussed how venting, additives, waste component systems, and holding tank blockages can play a role in odor control in your RV. Today, I’ll discuss the actual procedures for dumping your tanks.
Correct Evacuation Procedures
1. Always wear disposable protective gloves.
When handling any waste system component, always wear throwaway latex or rubber gloves and be sure to wash your hands thoroughly afterwards. No need to take undue risks.
2. Connect the sewer hose to the termination outlet and the sewer inlet.
Unless you are equipped with Phase Four’s Waste Master system with its permanently installed hose and nozzle, you’ll need to remove the sewer cap and attach the sewer hose adapter. Make sure the seals are in good shape. Inspect the seal on the cap and the adapter periodically. Seals are easily replaced so there is no excuse for having dripping hose connections.I recommend using a clear sewer adapter at the hose connection or a clear fitting at the sewer inlet in order to check the cleanliness of the water as you flush each tank after evacuation. Be sure you have the correct elbow adapters on hand to securely affix the bitter end (open end) of the hose into the park’s sewer inlet. No leaks allowed here either!
Keep in mind there is no standard size sewer inlet mandated for RV parks or dump sites; you’ll find everything from 3-inch to 4-inch to even 5-inch or larger inlets. Be prepared! Do not just simply stick the open end of the hose down the sewer inlet allowing tank odors and park septic odors to escape. Also, use the shortest sewer hose as possible. Do not use that 20-footer for a 6-foot run and have it snake back and forth between the coach and the sewer inlet. (This is why I recommend the Sewer Master hose… extend it only as far as you need!) And be sure to maintain the proper slope of the drain hose. Remember water and waste cannot flow uphill!
3. Only evacuate a holding tank (black or gray) when it is over ¾ full.
Yes, this means not leaving the gray valve open while in the campground – the total opposite of what we’ve been taught for years. Filling each tank above the ¾ mark before evacuating will ensure you’ll have enough volume (and velocity) to thoroughly drain that tank and flush the hose at the same time. A slow flow of a small amount of water will not gather much steam or be able to rinse away any stubborn deposits in either holding tank.Here’s another reason for keeping the gray holding tank valve completely closed except while evacuating – ever walk through a beautiful, scenic campground and catch a whiff of sewer odor wafting through the park? Kinda ruins the moment, huh? All those coaches with the gray tank valve in the open position (sewer hoses obviously connected), are simply acting as a direct conduit to the park’s sewer system. Each coach becomes a mini-vent system for the septic system of that campground. No wonder sewer odors still abound in the nicest of destination locations!
Follow the logic; a large septic tank or waste management system in a campground will have intrinsic venting designed into it for sure, but with numerous motorhomes and travel trailers connected to that system with their gray tank valves open, odors rise up through the septic system, through the sewer hoses of those RVs, through the empty gray holding tanks and up the vents of those holding tanks. Remember, it may be your gray tank, but it’s the campground’s black and gray odors coming up and through! The only problem with this scenario is that the gray tank vents on the RVs are a lot closer to the ground than the park’s own sewer vent so odors are more noticeable. But by keeping the gray tank valve closed until the tank is almost full you will eliminate the localized (at your site) venting of the park’s sewer gasses. The more people who follow suit, the less likely we’ll have to endure septic odors in and around the campsite.
4. Evacuate the black tank first.
This is pretty much standard procedure now and something most all RVers are aware of, but it’s worthy to mention it again. After the black tank empties flush it out with a large amount of fresh water if you are connected to city water. Simply keep flushing the toilet. Monitor the cleanliness of the water through the clear hose adapter. When the draining water is relatively clear, stop flushing, close the gate valve and cover the bottom of the tank completely with fresh water. Permanently installed holding tank spray kits are available that attach to each holding tank thereby allowing fresh water to be directly induced into the tank after dumping, but I’m hesitant to drill mounting holes into holding tanks. Plus I like to flush all components of the waste system including the toilet, sink drains, etc., so I prefer to simply flush the toilet and run water in the sinks. Treat that tank with RM Tank Care at this time.
5. Evacuate the gray tank last.
After the black tank has completely emptied and the termination valve is closed, open the gray water valve and empty that holding tank. Be sure to rinse this tank as well and cover the complete bottom of the tank with fresh water afterward. Dumping the gray tank last utilizes its liquid contents as well as the fresh water added after dumping to help clean any solid waste that may remain in the sewer hose. Add the RM Tank Care to the gray water holding tank as well.
6. Drain the sewer hose.
After both tanks have been emptied for the last time at that location, take the time to “milk the hose.” Raise the hose at the closest point near the termination outlet on the RV and walk it towards the sewer inlet. Keep raising the hose as you walk, thereby “milking” the hose and emptying it completely of water and waste. Even a properly sloped flexible sewer hose will have residual water and waste particles left inside. These particles will become an odor generator over time, so it’s imperative in an open system, (one without a positive shut-off valve at the sewer inlet), to completely remove as much moisture as possible.
7. Check the “P” traps.
Every month or so, look down each sink drain and the tub/shower drain to ensure the water seal is still there. You’ll probably have to use a flashlight, but it is imperative that a water lock remains at all times. This is the principle method of preventing gray holding tank odors from entering the interior of the RV. In some waste system designs, a quickly draining tank can cause that water lock to be siphoned out of the trap. Remember, a dry “P” trap is nothing more than a shortcut for odors to gain entry into your RV.
8. Be sure the toilet bowl contains water at all times.
If water eventually seeps past the seal and the toilet bowl empties, it’s time to make an appointment at your local service center. An empty toilet bowl will allow black tank odors into the RV. If water can leak past the seal, vapors can also!
Final Thoughts
Realize that these are simply my recommendations based on my evaluation and testing of these products and services. I strongly encourage you to perform your own due diligence. Contact the suppliers I have mentioned in this series (or competing suppliers, for that matter), and have them convince you as to why you should be using their products and services. I have found, however, that the implementation of the above products coupled with the correct evacuation procedures, holding tank odors can be effectively eliminated… forever! Remember, RVing is more than a hobby, it’s a lifestyle!
Gary Bunzer, The RV Doctor