Unlike a house where the toilet, shower, and sink detritus can be flushed or washed far and away, an RV carries its waste around inside its belly, sometimes for days or weeks at a time. During this time, odors from whatever went down the drain can creep back up into the RV living space. This makes for some unpleasant conditions on an otherwise pleasant trip.
An RV grey tank is usually the less likely culprit when it comes to smells. The grey tank is the holder of water from sinks and showers. However, soap scum, hair, food waste, and a moist environment can release moldy odors from the grey tank or sinks into the RV.
The best way to get rid of a grey tank smell is to make sure that no food goes down the kitchen sink, use a holding tank treatment, and regularly empty the tank at a dump station.
But what if there are still lingering odors? Why does my RV smell like sewer?
The main culprit of sewage odors will be your RV black tank.
The smell that needs to be dealt with immediately is the stink caused by a much worse effluent. If you are going to use your RV toilet for both Number 1 and Number 2, knowing how to clean out and maintain your black tank is an essential RV skill.
An RV black tank is usually located in the underbelly of the RV. It contains water, waste, and toilet paper from an RV toilet. Emptying and maintaining a black tank is probably one of the most dreaded jobs of any new (or veteran) RV owner.
Don’t worry. Once you take a little time and get the hang of it, making sure the tank is healthy should keep any odors away from your RV life. The tips below should help. Consequently, if you have a smaller RV that combines the grey and black tank into one, you can also follow these tips below.
1. Prevent RV tank clogs
Preventing any clogs is the first step to maintaining a healthy tank. The best way to do this is to avoid putting anything but RV-safe toilet paper down the toilet. If you can handle it, don’t even put your toilet paper down the toilet at all. Instead, do what they do in areas with sensitive plumbing and put it in the garbage.
If you do have a clog, this excellent post by Camp Addict has a step-by-step process to clean out the tank from the dreaded pipe clog or the poop pyramid.
2. Keep plenty of water in the tank
Preventing tank clogs and odors will go much smoother if the black tank always has plenty of water in it. Waste from the toilet needs to be mixed with fluids so that the tank and the solids within it don’t dry out and cause odors. There are several ways to do this.
One way is to make sure to flush after each use of the RV toilet. Adding a little more water down the toilet drain is also useful if your…um…deposit was generous. In addition, the rule of thumb for adding water into the tank is to make sure that the bottom of the tank is completely covered with water. You can monitor this on your black tank sensor or make sure you flush down about four to six tanks of fresh water from the toilet.
3. Empty the tank before it gets full
To avoid odors even further, make sure that when you empty your black tank, you do it before it gets full. This will require another monitoring of the black tank sensor. You should plan to dump your tank at around the 3/4 full mark since this will allow for one or two extra flushes before the tank actually fills to the brim.
At the time you are dumping the black tank, this is also a good time to do a good, if not thorough, clean of the tank. This excellent video by RVgeeks shows not only how to empty and scrub out a black tank, but also how to do a “sniff test” using your bathroom vent fan:
4. Regularly clean and maintain the toilet gate valve
There is really only one simple part that keeps odors from wafting up into your RV bathroom and that’s the RV toilet gate valve. It’s imperative to keep this valve (or flapper) clean and in good repair. The seal around the valve is also an important part in that it holds a small amount of water at the bottom of the toilet. This water will hold back any smells that linger in the toilet or the tank.
If the toilet gate valve is dirty, it may not close and keep that seal tight. Take a wet rag and thoroughly wipe around and under the valve to remove any debris. This is also a good time to check the valve seal for cracks.
5. Keep your tank’s gut happy
Just like your tummy, your tank is happier when full of enzymes. One of the best products for both tank treatment and odor control is Happy Campers RV Holding Tank Treatment. The treatment is a blend of minerals and micronutrients that both treats waste and eliminates odors without perfumes. One scoop will work for a 40-gallon black tank, and the product will also work fine in your grey water tank.
Hopefully, this article helps you answer the question, “Why does my RV smell like sewer?” Make sure you keep track of all your RV maintenance and repairs with an online tool such as RV LIFE Maintenance. Not only can you keep all of your documents in one place, but you’ll also receive timely reminders when maintenance is due to help you avoid costly repairs and potentially serious accidents.
