Do you keep your RV gray valve open? Closed? How about BOTH?!

Leaving your RV’s gray valve open when fully hooked up allows you to take long showers without worrying about dumping or filling up the gray tank. But what about sewer smells that can come up from the campground sewer system? Here’s how to get the best of both worlds!

One of the luxuries of staying in a full-hook-up campground is the ability to use water freely for showers, cooking and washing dishes. The sewer connection allows you to leave your RV’s gray valve open, so water can run right out instead of filling up your gray tank.

Of course the black valve can NEVER be left open, since “solids” will build up in the black holding tank when the “liquids” run out. But there’s a fair amount of discussion about the gray valve. Some people recommend that you should never leave the gray valve open either, as it can allow odors from the park’s sewer system up into your RV.

Leaving the gray valve closed does mean having to pay attention to the water level in the gray tank, and dumping it every few days. Seems like a shame to have to do that when your RV is connected to a sewer line, especially when you’re staying in a full hook-up site for an extended period of time.

Even though the drains under every sink and shower in an RV are equipped with a p-trap, there is a pipe with a direct connection to the sewer hose…. leading to the tank vents on the roof of the RV. This can allow air from the sewer system to come up through the roof vents. If you’ve ever smelled sewer odors in a full hook-up campground, it’s possible that someone’s RV is venting the park’s sewer system out through their roof.

In a recent RV Travel newsletter, we read about the simplest way imaginable to enjoy the luxury of a full hook-up RV park. You can leave your gray valve in the open position so water runs right down the drain. You don’t have to pay any attention to how full your gray tank is and you don’t have to dump it every few days. But there’s no chance for sewer odors to escape either. It’s the best of both worlds.

Watch the video to see how to do it!

Please use your full hook-up powers responsibly and don’t waste water!



Just a brief follow-up... Although this wasn't a video about tank dumping, it is related, and there were some comments and questions about it. If the gray valve is left open, there isn't any gray water available to flush the sewer hose after dumping the black tank. Here's how we handle that.

Conserving water and monitoring tank levels are just part of life for most RVers, so it's a luxury to be able to forget about it once in a while. When we're in a full hook-up RV park for an extended stay, leaving the gray valve open allows us to take longer showers, while completely ignoring the level in the gray tank. We just use the trick we demonstrated in the video to prevent sewer odors from coming in through the open gray valve.

Then all we need to do is keep an occasional eye on the black tank level. Since we often take the load (sorry) off the black tank by making periodic use of the park's bathrooms (as long as they're clean), it takes a solid (sorry again lol) two weeks or more to fill it up. When it shows 3/4 full, we close the gray valve for a day or two, allowing gray water to accumulate in the tank.

When we're ready to dump, we take a few seconds to put the entire sewer hose back up on the sewer hose support, then dump both tanks, black first of course. Plenty of water has now accumulated in the gray tank, allowing us to flush the sewer hose after dumping the black tank. When we stay in one place for an extended period, we appreciate being able to completely ignore both tanks for two-plus weeks at a time. This way of managing our tanks allows us to do that.

This is a perfectly fine way to handle shorter stays too. After boondocking for extended periods, we'll sometimes treat ourselves to the luxury of full hook-ups for a week or so, leaving the gray valve open and using the same sewer hose technique. We simply close the gray valve a day or two before we'll be leaving the park, and dump both tanks on the morning of our departure.

We don't pretend to be experts on any particular RV topic, and mostly know about maintaining our own rig. But many systems are the same on different RVs. The advice we give works well for us, but be sure to consult a professional technician if you're unsure about working on your own RV.

How To Calibrate RV Tank Monitors

Since we're sometimes pretty serious boondockers (that's camping without hook-ups for you RV newbies), we want to know the exact levels in all of our holding tanks - fresh water, gray water and black water - and our propane level too.

We have a fresh water capacity of 105 gallons, 65 gray and 45 black. The limiting factor for boondocking is always the gray tank. We can easily spend 7 days out in the desert, with both of us showering every day, cooking every meal on board, doing dishes etc. If we know we're going to want to stay in one spot longer, we can make it up to 10 days by being REALLY frugal with water. When the gray tank is full, we always have about 1/4 tank of fresh water left, and the black tank usually takes about two weeks to fill.

A key part of knowing how long you can stay in one place without hook-ups is knowing the levels in your fresh, black and gray tanks. This video will show you how we calibrate our tank monitors so we always know where the levels are. Tank monitors vary by make and model, but this will give you an idea about how we calibrate our Newmar monitors.

This is not something that needs to be done on a regular basis. We calibrated our tank monitors shortly after purchasing our motorhome, and have never needed to touch them since.



We don't pretend to be experts on any particular RV topic, and mostly know about maintaining our own rig. But many systems are the same on different RVs. The advice we give works well for us, but be sure to consult a professional technician if you're unsure about working on your own RV.

How to Dump RV Holding Tanks

Dumping your RV's black and gray tanks might seem like a no-brainer, but we can't tell you how many times we've seen people who could use a little help with the basics. Properly dumping your RV's holding tanks requires a few simple procedures to help keep things odor-free and running smoothly.

For everyday tank dumping, this video is the "express version" of our original "How To Dump & Clean an RV Black Tank." If your black tank really needs a super cleaning, you can watch the original, more detailed video here.

If you're not having tank odor problems and just want a quick overview of basic tank dumping procedures, this new video gets right to the point.

Many RVers seem to think their black tank is clean when they just empty it and flush out the sewer hose with water from the gray tank. Even those RVers who use a black tank flush system often don't utilize the most important piece of equipment necessary for monitoring the cleanliness of the tank: a clear sewer elbow.

But using a clear sewer elbow isn't enough. As we demonstrate, even a black tank flush connection still won't do the job unless used correctly. We show you how to be sure your black tank is really empty, keeping it clean & odor-free and making your RV a nicer place to be.



To find clear sewer elbows on Amazon, click here.

We don't pretend to be experts on any particular RV topic, and mostly know about maintaining our own rig. But many systems are the same on different RVs. The advice we give works well for us, but be sure to consult a professional technician if you're unsure about working on your own RV.

How to Clean an RV Gray Tank & Sensors

Besides water, an RV gray tank (or "grey" if you trend more British, like us Canucks) takes in lots of greasy, sticky substances. These include food particles & residue from preparing meals and washing dishes, soap, shampoo, toothpaste & even body oils. After a while, it can gum up your holding tank sensors, causing a false reading on your tank monitors.

Cleaning the gray tank and sensors is a really simple task, since there's a readily available liquid designed to break up all of the crud that can build up in the tank. This short video will show you how.



We don't pretend to be experts on any particular RV topic, and mostly know about maintaining our own rig. But many systems are the same on different RVs. The advice we give works well for us, but be sure to consult a professional technician if you're unsure about working on your own RV.