Installing a Grey Tank in a Nomadic Home

A big part of our nomadic plan is to be able to travel anywhere. The problem is that we bought a used 2009 Palomino Bronco 1500 which doesn’t have a grey tank to capture the sink water. What it has is a passthrough pipe to displace the sink water on the outside of the truck. In most places releasing grey water (sink/shower water) willy nilly like this is at best frowned upon and in other places, it is downright illegal. 2009 doesn’t seem like that long ago. It is hard to fathom that this was still an acceptable practice to the extent that manufacturers were making campers without grey tanks, but here we are. For all I know they still do. So this post is about the way we went about installing a grey tank in our nomadic home.

The Bathroom Remodel Provided Space for Our Grey Tank

The Thetford Cassette Toilet
Remodeling our bathroom for the Thetford Cassette toilet gave us the room we needed for installing a grey tank. Click the image to see our review of the Thetford Cassette toilet.

I should say that our way was made possible by removing the manufacturer’s toilet/shower combo and putting in a Thetford Cassette Toilet. Click here to check out how we did that install. There are many other options for where one could place a grey tank in the Bronco 1500 or other types of truck campers and campervans so even if you aren’t removing a shower hopefully this post will give you an idea for how you can plan for a similar renovation of installing a grey tank in your camper or RV.

Be a Good Nomad and Use a Grey Tank

I highly recommend a grey tank and it should be mandatory when camping near others or urban environments. Even if you use eco-friendly soaps (which we do) and a sink strainer no one camping near you wants to smell your sink water and it can attract large animals to areas where they don’t belong. In many states, it is now illegal to dump grey water so you need a grey tank if you want to travel freely.

Pre-Installation: Plumbing Dimensional Nightmares

Plumbing under the sink when installing a grey tank in a camper.
Plumbing a grey tank inside an RV can be intimidating but if I can do it you can too.

I need to preface our process of installing a grey tank by saying that plumbing is the worst. There are at least three different standards (NPT, MIP, AN, the list may go on; I’m not a plumber) and they are all slightly different so getting tubing and fittings to line up at times seems impossible. Most fittings are listed by their ID (Inside Diameter) but some are listed by OD (Outside Diameter) and there is also a multitude of different connectors (screw down, barb, push to fit). Of course, if you don’t get the right pieces then they won’t fit or worse you can end up with a leak. All that to say I bought and returned a lot of pieces that dimensionally should have fit but for a multitude of reasons did not.

Another issue with camper plumbing is that it isn’t the same as home plumbing. Home plumbing mostly uses copper or PVC pipes. The RV industry seems to use a lot of flexible hose and tubing. I can’t say this is true for all manufacturers but it was in our case. I guess it allows for more flexibility when the camper is in motion although they use copper for the propane lines so who is to say why this is the case.

Our Grey Tank – A Barker 12 Gallon Tank

Our chosen tank is a Barker 12 Gal water tank kit hoping that the kit would come with enough pieces that making the connections would be easy… I was wrong. I primarily choose this tank because the 20″L x 12″H x 12″W fit my desired install spot perfectly and it was premanufactured and ready to ship with threaded fittings. The Barker tank is meant to be used with a 1-1/4″ bilge hose or pipe for the intake. This is a standard size for a freshwater holding tank, but not ideal for the 3/4″ outlet from our sink. The threaded outlets on the Barker tank are small and odd. 3/8″ is very small for grey water usage and it is a hard connection to find. 3/4″ or even 1/2″ would be better for easily sourcing fittings at local hardware stores.

Other Grey Tank Options

Most grey tanks are not manufactured for the individual consumer but rather RV manufacturers. There are a few custom manufacturers out there who will either build a tank from specific dimensions or have templates that hole patterns can be customized for. Or if you are really a DIY person you can cut your own holes and install the connections yourself. The price for customization obviously can have a very expensive price tag and long turn-around times. We, like most other DIYers, were looking for a good affordable solution and found it. Warning! When it comes to plumbing, affordable = installation frustration.

Alternative Grey Tank

If a full renovation isn’t something you wish to undertake in order to catch your grey water there are portable containers designed to attach to the drain port and catch water as it exists the camper. My biggest concern of these tanks would be them freezing in colder weather. There are also a lot of reviews about them tearing up fairly easily. The small 5-gallon size wouldn’t give travelers much time between disposal stops but it would save you some renovation hassle.

Installing the Grey Tank- Modifying the Barker Intake Pipe

A grey tank installation with the tank fittings.
The main intake on the grey tank was modified with the grey barb connector. The holes I placed in the bathroom wall to flush mount the tank are also visible in the image.

Our factory sink has a 3/4″ outlet. The Barker water tank has a 1-1/4″ inlet. To overcome the tanks larger intake size I used a 3/4″ NPT right-angle to a 3/4″ barb connector to modify the intake. I believe this piece is intended for sprinkler systems.

To modify the tank, I first used a pipe cutter to cut off about 1″ of the protruding intake pipe on the tank. It comes with about 2″ which was too long for my preferred mounting location. I then heated the remaining pipe piece with a heat gun to make it malleable. While it was hot I screwed the 3/4″ right-angle piece into the pipe and let it conform to the threads. Once the pipe had re-hardened I unscrewed the right-angle piece and liberally applied PVC glue to the connection before screwing it back into the tank. Once in the desired position, I made sure the right-angle connector was clear of glue as it would have been easy to accidentally glue the intake shut. I allowed the glue to dry for several days before continuing the tank installation.

Modifying the Bathroom’s Cabinet Wall

The Bathroom Cabinet Cavity with installed Grey Tank hoses.
The hoses and connectors for the Grey Tank are hidden inside this 2″ cavity in the bathroom wall.

In the meantime, I cut three holes in the bathroom cabinet wall so that the tank’s connectors sit behind the wall when fully installed. The holes are for the intake, outlet and air release hoses. My bathroom wall has a 2″ deep cavity behind it so I wanted the tank to butt up to the wall and the connectors and hosing to sit in that cavity. My other goal for our grey tank installation was to keep all the hoses inside the camper so they wouldn’t have the opportunity to freeze in the winter. For this reason, all three ports needed a right angle connector.

Repurposing the Drain Port as an Air Release

Grey tank air release
This threaded outlet on the Palomino Bronco 1500 camper was originally the drain port for the sink. I repurposed it to be the air release for the grey tank.

Next, I moved to the sink area. I removed the factory installed hose that ran from the sink to the drain port. The drain port is the piece that passes through the camper’s wall to the outside of the truck. I then attached a new section of 3/4″ hose to the drain port. I am repurposing this port as the air release which is needed when installing a grey tank. An air release equalizes the pressure in the tank. Without an air release, emptying the grey tank would be a very slow process and the sink might not drain at all. It was nice to have this drain port so that I didn’t have to cut any additional holes in the camper’s exterior walls.

Running the 1/2″ Air Release Tube Through the Sink Cabinet

air realease hose under sink cabinet
The 1/2″ hose used as the air release is mounted to a right angle connector under the sink cabinet. The larger 3/4″ right-angle connector is mounted and waiting for the tube. This is where I terminated the lines to ensure proper length after the tank was in place.

From the drain port, I ran a 3/4″ hose to a 3/4″ barbed T-adapter for the air release above the water trap. I’ll explain the reason for this further below. From the T-adapter the hose continues on to a 3/4″ to 1/2″ right-angle adapter which passed through the sink cabinet’s floor. A hole was needed here so I drilled a 1″ wide hole through the cabinet’s floor. I only made the hole big enough for one end of the right angle barb to pass through so I had to attach the hose to the barb connection while it was in place.

Running an Air Release Tube when Installing a Grey Tank

Once through the sink cabinet, I used a 1/2″ hose for the air release and ran it along the inside of the camper underneath the overhang for the kitchen cabinets and through a hole I drilled in the wall leading into the bathroom area. Here, I used a 1/2″ right-angle barb connector to turn the hose 90 degrees and entered into the wall located behind the intended spot for the grey tank. I ran the hose down the cavity in the wall and eventually (once the PVC glue from the step above had dried) onto the 1/2″ to 3/8″ right angle barb connection located at the top left part of the tank. I actually attached this hose to the tank first and once the tank was in place attached it at the connection point under the sink cabinet. This allowed me to make the hose as short as possible.

Using a Bilge Hose for the Water Trap

Next, I returned to the sink area and attached and ran a 3/4″ ID bilge hose from the sink’s catch basin. I used a bilge hose here because it is more flexible than traditional tubing and allowed me to easily put a bend in the pipe. This bend in the pipe creates a water trap which is essential in plumbing and an important feature when installing a grey tank.

A water trap is created when the hose dips enough to allow water to sit in it completely blocking the passage of air. This keeps smells in the tank from escaping back into the living area by creating a water barrier. I should say here that this works really well when stationary but as the truck moves the water sloshes out eliminating the barrier. We use a rubber stopper in our sink to keep the gases from escaping when traveling. When we pull that stopper out we do often get a good whiff of the foul odors. A good option to combat this is to put a ball valve in the drain line allowing it to be closed off while traveling. It is one more thing to remember to do so we haven’t done it and the odors only last until we reintroduce water into the system.

Air Release for the Water Trap

Air and Water flow for installing a Grey Tank
This image hopefully makes it easier to see how all the added hoses under the sink work to deliver water to the grey tank as well as air to equalize the pressures.

I attached the other end of the bilge hose to a 3/4″ T-adapter that then runs up and connects to the air release’s T-adapter that I covered in the air release section above. It is necessary to add an air release near the water trap to keep from creating suction in the drain line that would otherwise pull the water out of the water trap. By introducing air into the line just after the U-shaped water trap the pressure is released allowing water to stay in the trap.

Drain Hose to Grey Tank

The drain and air release tubes for installing a grey tank
The hoses run underneath the kitchen overhang perfectly concealing them from the living space.

The other side of the 3/4″ T-adapter runs down to a 3/4″ right-angle barb piece that I ran through the floor of the cabinet right next to the one for the air release. I, of course, had to drill another 1″ hole here as well. Once again the hole was only large enough to slide one end of the right-angle piece through so I attached the hose to the barb in place.

From the 3/4″ right-angle adapter I attached a 3/4″ braided hose that then followed the 1/2″ hose’s path to the tank where it eventually connected to the larger 3/4″ intake barb that we glued into the tank earlier. Again the 3/4″ hose was attached and once the tank was in place we were able to get a perfect length and attach the hose under the sink. Once everything was in place I used some zip-ties with a screw loop to affix the hoses to the underside of the cabinet. One zip-tie every foot.

The Grey Tank’s Release Valve

Mounting a water release valve for the grey tank was next. I used a water hose spigot with 1/4 turn ball valve. This allows us to attach a garden hose to it and channel the water into a cleanout, a flower garden or other locations so we don’t just dump the water behind the vehicle. Again the only thing in the grey tank is sink water which has some environment-friendly soap and perhaps some food particles in it so it is environmentally okay to dump this almost anywhere although the legality will depend on where we are at the time. In my mind, the most important thing is to not dump it where everyone else is camping.

Grey Tank Water Spigot
I used a water spigot with a ball value as the release mechanism for the grey tank.

I mounted the spigot on the bottom of the camper along the back edge where it extends past the truck bed. This is where the shower release valve was mounted before I removed it during the bathroom remodel. I had to close the former holes left by the removed bathroom plumbing so I mounted the water spigot to the board I used to close off the space.

From the Grey Tank to the Release Valve

The last hose I had to run was a 1/2″ hose from the bottom of the grey tank, through the cavity in the wall and to the release valve at the back of the camper.

Connecting All the Hoses at the Grey Tank

Installing a Grey Tank Flush Mounted
The grey tank is flush mounted to the bathroom wall so all the connections are hidden inside the wall.

I attached all 3 hoses to their terminals at the grey tank and pushed it into place. Once the 3 hoses were attached I slid the tank into place and then pulled all the hoses to their proper length, cut and finished attaching the connections.

Sealing the Connections

I used pipe thread sealant and screw down clamps on all the water tube connections throughout the entire system and all the connections at the grey tank to ensure we didn’t have any leaks. Be careful not to use too much sealant as you can accidentally block a hose with it.

Installing a Grey Tank

Grey Tank stop block
A simple stop block is used to keep the grey tank in place. The tank we bought had an extra port on it. I used PVC glue to make sure the plug doesn’t slip.

To keep the tank in place I screwed two stop blocks into the floor on two sides of the tank wedging the tank into the corner of the bathroom. I also used a large velcro strap across the top to keep it from bouncing around when the truck is in motion. This combination effectively holds the tank in place on the roughest of roads.

A velcro strap used for installing a grey tank
I used a velcro strap across the top of the grey tank to hold it in place.

Testing the Seals

Once the tank was in place and the sealant had ample time to dry I tested all the seals by running a lot of water through the sink and into the holding tank. I checked all the seals while the water was running. Once the tank was nearly full I released the external valve and checked all the seals again. No leaks!


Palomino Bronco 1500 truck Camper bathroom renovation
Our bathroom renovation complete after installing a grey tank. This is what is needed for a life of full-time travel.

We’ve been living with this system for a while now and it works really well. My only real complaint of the tank itself is that the 3/8″ ports aren’t common and are a little small. We haven’t had any clogs which I was initially concerned about. I think the strainer we use at the sink is the real reason we haven’t had any clogs. Another small complaint is that the tank came with sharpie writing on top of it. I guess most people hide these tanks away, but I didn’t want to create unnecessary weight by adding a housing so ours just sits out in the open. One of these days we might just cover it with paint or travel photos.


If you found this post helpful and do intend to purchase a 12 gallon Barker Manufacturing Company tank or any of the parts of this system please support by using the links provided on this website. There is no additional cost to you, but we will receive a percentage of your purchase to help us continue to provide helpful travel information to everyone. Thanks!

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5 Comments Add yours

  1. Todd says:

    Great explanation. I have to do this sometime this year and boy, i am not looking forward to it!
    Todd recently posted…Best Drain AugerMy Profile

    1. NomadicMoments says:

      Plumbing is the worst! I would rather rewire my solar system 5x over than to have to get the correct plumbing pieces for this kind of project figured out again. It is nice now that it is done though. Especially in our current “Corona” state. We’ve been boondocking for 8-days at a time to social distance. Couldn’t do that without our 12 grey tank!

  2. Happy Hiller says:

    What are the pros and cons of owning an RV?

    1. NomadicMoments says:

      We generally do not think of ourselves as owning an RV. RV’s are typically massive and must stick to major highways and interstates. They can also be hard to park and not allowed in certain areas including some national parks. That being said here are our pros and cons to living in a truck camper: href=””>

  3. Thanks for sharing this post here with us. I loved the bathroom designs

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