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Key Points:

• Urine is mostly water, but the 5 percent that’s not can cause increased odors when it blends with bacteria in the black or gray tanks.
• Always use high-quality, bacteria-based tank treatments on both the gray and the black tank; how you use these treatments varies depending on how you are camping.
• Gray/black combo tanks can probably handle some urine depending on how you’re using it.
• Best practice is to just not pee in your RV shower.

Who hasn’t peed in their home shower? Well, it seems that the nation is split almost 50/50 on that point, some enthusiastically admitting it and others recoiling at the thought. Peeing in a home shower is one thing, but what about peeing in an RV shower? As with almost any topic, there are nay-sayers and supporters on both sides. In the case of RVs, the nay-sayers win the day. In this article, we’ll explain why you should NEVER pee in an RV shower (with one exception) and how you can actually avoid odors by keeping urine exclusively in the black tank.

What is Urine?

Urine is mostly made up of water, but there’s about 5 percent of it that is made up of other elements of bodily waste acids, and the combination of these elements is what gives it a smell and varying shades of yellow. One of the things that does not make up urine (contrary to common belief) is bacteria. Bacteria is not a component of urine while it’s in the bladder. There are a lot of sites out there that will tell you that urine is sterile and has very little bacteria in it, and that’s true while it’s sitting in the bladder. Bodily infections (that you may not even know exist yet) can cause more bacteria to be present in the urethra (the pathway out of the body), which means the urine can start out sterile and then pick up bacteria on the way out.

Secondly, the claim that urine is sterile doesn’t mean it should be put into the gray tank without another care. Even if urine leaves the body bacteria-free, it will mix with the grease, oils, soap scum, flaked skin, and other organic matter that is laced with bacteria, and urine combined with bacteria can cause some pretty vile odors. Will the same thing happen in the black tank? Yes, of course it will. Human feces has bacteria in it, which means urine added to the black tank will mix with that bacteria and smell worse as well. However, black tanks were designed to include all human waste, solid and liquid. Gray tanks usually are not.

Note: For more details on the make-up of urine and why you need more than just urine and poop in your black tank, refer to our guide on Urine Is Not Water - Using Water In Your Holding Tank.

Urine Belongs in the Black Tank

Our answer to the question of whether or not you can pee in your RV shower is no. We’ll admit that urine in the gray tank won’t necessarily hurt anything, but if we’re recommending the best course of action based on science, then the answer is don’t allow urine in your gray tank. There are talkers online who advocate that peeing in the shower is actually more sanitary and helps conserve water (less splashback, no contamination because you’re washing yourself anyway, saves the water flushing would use, etc.), which may be okay for a home shower that is hooked directly to a city sewer system or a septic system, but RV holding tanks work a lot differently. As the name suggests, RV holding tanks “hold” wastewater until you can dispose of it properly. 

So you may wonder, why does it matter if urine is in my gray tank? The biggest reason is because keeping human waste in one dedicated tank is the most sanitary storage option and allows you to more appropriately treat the waste. All you're doing is storing waste until you can appropriately dump it, and by separating dish, shower, and hand washing water from human waste, you can properly treat the contents of both tanks so you avoid odors and clogs until you can dump.

Always Treat Gray and Black Tanks with Bacteria-Based Products

Whether you are a stickler about not peeing in your RV shower or believe it’s not a big deal, you should still be treating both of your tanks with a bacteria-based product (like Unique RV Digest-It Plus). But, how you use products like this will depend on how you’re camping:

• If you are boondocking (short term or full-time), it’s best to treat your gray and black tank with a high-quality bacteria treatment like Unique RV Digest-It Plus.
• If you are camping on sewer hook-up (short term):
  • Treat your black tank with RV Digest-It Plus and keep the black valve closed.
  • There is no need to treat the gray tank because you’ll likely leave your gray valve open on hook-up. We still recommend performing a deep clean of your gray tank with Dawn Ultra the night before you leave the campsite.
• If you are camping on sewer hook-up (full-time):
  • Treat your black tank with RV Digest-It Plus and keep the black valve closed.
  • Once a week, close your gray tank valve and treat the tank with RV Digest-It Plus. Use it normally until it’s full; dump the tank and leave the gray valve open. Repeat the following week.

If you are consistently treating your gray tank as described above and regularly deep cleaning it, you shouldn’t have to worry if urine makes it in there once in a while, but we definitely don’t recommend making it a habit. Besides, there is science out there that says if you habitually pee in the shower, you’ll start feeling the need to pee every time you hear running water. That could make things interesting! So just opt for a short detour before hopping into that soothing spray.

Guide: Deep Cleaning RV Wastewater Holding Tanks

Guide: Full Time RVing: The Definitive Guide to Treating Your Tank

Gray/Black Combo Tanks

You might be thinking you can catch us off guard when you say, “Well, I have a combo tank, so it really doesn’t matter for me, right?” Maybe. A combo tank just means you could use it for both or one or the other types of tanks. Some people use combo tanks only for gray water and do all their potty business in the wilderness or in campsite facilities; others use it only for human waste and do all their cooking and washing outside. With these situations, you still may need to watch what goes into that tank, but for those who really are using it as a combo tank to store a mixture of human waste and gray water, it probably doesn’t matter if you pee in the RV shower as long as you are treating the tank with a high quality, bacteria-based treatment and aren’t phased by that psychological suggestion that you’re training yourself to need to pee at the sound of running water.

Review

While the topic might be a little difficult for some to talk about openly, the scientific best practice is to not pee in your RV shower. But we at Unique Camping + Marine will admit that even we have differing opinions about whether or not it’s ok to pee in your RV shower. As long as you are using The Unique Method, you should have a problem-free camping experience even with urine in your gray tank. Here’s a brief review of what we discussed in this guide:

• Urine is mostly water, but about 5 percent is made up of the stuff that causes smells and the yellow color.
• Regardless of whether or not the urine has bacteria in it when it comes out, it will connect with bacteria in either tank and will boost odors.
• Black tanks are designed to hold urine; gray tanks typically are not.
• Always use high quality, bacteria-based tank treatments on both the gray and the black tank; how you use these treatments varies depending on how you are camping.
• Gray/black combo tanks may have a little wiggle room handling urine in conjunction with gray water, but it all depends on how you’re using your combo tank.