DIY Van Help
Contents
The goal of this article is to provide an overview of the design and installation of our water system in our campervan. Our water system includes the following components:
- Fresh water system:
- Fill inlet for filling the fresh water tank.
- 16 gallon fresh water tank.
- Screen filter, electric pump, accumulator, and ½ micron filter.
- Sink with a dual-spray pull-down faucet.
- Grey water system:
- P-trap to prevent grey water odors from entering living space.
- 8 gallon grey water tank mounted under the van.
- Drain outlet with removable flexible discharge hose to drain grey water.
Background
In October 2019 we upgraded the water system in our campervan. Our first water system used two jerry cans to hold fresh water and one jerry can for grey water. This system worked fine, but there were several reasons that convinced us to upgrade. To fill up on fresh water and dump the grey water we had to pull all of the jerry cans out of the sink cabinet, fill at the water fill station and dump the grey water, and then carry them back into the sink cabinet. There were several annoyances in this process:
- We keep a lot of stuff in the sink cabinet in front of and on top of the water tanks. We had to unpack all of this stuff every time we filled our water.
- After filling we had to make sure the tank wasn’t too full or else it would leak out of the top of the jerry can once in the sink cabinet.
- Once the tank is filled it weighs roughly 50 pounds, so lugging it back into the van and then into the sink cabinet isn’t the easiest process.
- Having grey water inside the van can get a little smelly. Grey water treatment formula works pretty well, but there is always still some lingering odor.
- It was very difficult to know how full the grey water tank was. In one instance we overfilled it and spilled grey water on our floor. It was a little gross, and we used a lot of vinegar to clean.
To overcome these problems, we designed the new system with the following features:
- A fixed fresh water tank with a fill hatch inlet. This eliminates unpacking the sink cabinet and lugging heavy tanks in and out of the van.
- A semitransparent fresh water tank. This prevents the possibility of overfilling.
- Grey water tank mounted underneath the van. This greatly reduces odors since the tank is no longer in the living space. It also means that if we accidentally overfill the grey water tank, the only thing that happens is that it spills on the ground beneath the van.
- Dump line with flexible drain hose. This allows us to dump grey water at dump stations without removing the grey water tank.
I’d like to thank Build A Green RV for the inspiration in the design of this water system. The main difference between our systems is that he built his grey water tank and I purchased it. Check out his site for additional inspiration.
Fresh Water System
Materials
Materials required in the construction of the fresh water system are shown in the table below. The order of the components in the table follows the flow of fresh water through the system, starting with the fill hatch inlet and ending at the kitchen faucet.
Flow Diagram
The flow diagram below divides the assembly of the fresh water system into three categories: filling, pumping, and supplying. The items in the diagram are clickable links to product pages. The blue arrows in the diagram indicate the direction of water flow. Application of thread sealant is shown in four areas. The area inside of the tank is outlined in a dashed box. We used a stainless steel fitting as a weight for the flexible hose so that it stays at the bottom of the tank.
Description
In the following sections we will describe each of the three categories of the fresh water system identified in the flow diagram: filling, pumping, and supplying of the fresh water.
Filling
We wanted the fill hatch for our fresh water system to be located on the outside of our sink cabinet, so that when you open the slider door it is easily accessible. This makes it a very simple process to fill up water at fill stations. It also prevents spillage from going into the van while filling.
Fresh water fill hatch closed. 
Fresh water fill hatch opened.
To attach the fill hatch we cut a 3.5 inch diameter cut out in the upper right corner of the sink cabinet as shown in the image below. We didn’t have a 3.5 inch hole saw, so we used the largest one we had and then used a jig saw to get the final diameter.
To hold our fresh water, we purchased a 16 gallon tank with a 5 inch tank lid. We looked at so many tank options, and it got to be quite overwhelming trying to decide which one to go with. I will give the reasons that we eventually chose this tank as maybe it will help others in the selection process:
- This particular tank fits really snugly in our sink cabinet. It is 14 inches wide, which is exactly the interior width of our sink cabinet. That means that it doesn’t budge, which is important as it weighs roughly 130 pounds when full. We found an 18 gallon tank that would also fit in our sink cabinet, but it was roughly twice the cost for only two more gallons of water. This didn’t seem worth the extra expense.
- The price of the tank is pretty reasonable compared to many of the other tanks we looked at. We actually bought this tank off of Amazon for $86.99 with free shipping. As of writing this article it is no longer available on Amazon, so I’ve included the link to the tank on plastic-mart.com.
- We like the 5 inch lid that comes with this tank. Many tanks designed for RVs, boats, etc. do not have any kind of lid, just NPT fittings for attaching plumbing. We like the lid because removing it allows us to get at any part of the interior of the tank. So if we ever get bad water, we can empty the tank and scrub the walls to clean it off. In addition, this particular lid has a spring-loaded vent, which means the water pump will not create an air vacuum at the top of the tank as water is pumped to the sink. And because it is spring-loaded it stays closed when the pump isn’t running, keeping the system leak-free while driving.
- One minor drawback to this tank is that there was no option to add fittings when ordering. This wasn’t too big a deal as bulkhead fittings are inexpensive. The two bulkhead fittings that we bought cost roughly $28 compared to the $20 to add standard fittings on other tanks we evaluated. There are also two benefits to going with bulkhead fittings over the standard fittings. One, you can place them wherever you want on the tank. Two, you do not have to plug any of the standard fittings that you do not use.
To install the 1-¼” FIP fill line bulkhead fitting into the tank, I used an adjustable hole saw to drill a hole into the top of the tank. See the pictures below. The bulkhead fitting is pretty easy to install. It includes a compressible gasket for creating a watertight seal to the tank, and a reverse-threaded nut to tighten the assembly onto the tank.
Fresh water tank with fill inlet hole drilled. 
Fresh water tank with fill inlet bulkhead fitting installed.
Although this section of the article discusses the fill portion of the fresh water system, I must briefly discuss the second bulkhead fitting which is used to draw water from the tank to the pump. The reason for this is that it would be impossible for me to drill the hole and install the bulkhead fitting after installing the tank into the sink cabinet. The ½” FIP pump line bulkhead fitting is installed in exactly the same manner, except with a smaller setting on the adjustable hole saw. Below are a couple pictures.
Fresh water tank with outlet hole drilled. 
Fresh water tank with outlet bulkhead fitting installed.
The picture below is the installation of the fill line inside the sink cabinet. When this photo was taken I wasn’t convinced that I would need thread sealant as the line would never be under pressure. However, when we tested the system it leaked, so I added thread sealant and fixed that problem. We used the spreadable thread sealant on larger fittings, and the tape on smaller fittings.
Pumping
You may have noticed that the pump line bulkhead fitting is on the top of the tank, which isn’t normally how these tanks are done. In normal RV fresh water tanks the pump line fitting is located on the side of the tank near the bottom (i.e., where there will always be water unless you are completely empty).
So why did we install our pump fitting on the top of the tank? Well, the main reason is a fear of leaks. Even though we have tested the system with water and it does not leak now, I would be a little weary of assuming that will be true after a year or two of driving the van all over the place. With potholes, dirt and gravel roads, and other road hazards, it is not always the smoothest journey in our van. I had a vision of hitting a nasty bump in the road, jarring the bulkhead fitting enough to start a leak, and then leaking 16 gallons of water into the floor of our van. That would be a nightmare.
However, with the bulkhead fitting on the top of the tank, even if it does eventually loosen over time, it won’t leak all 16 gallons into our van. At most, it might leak a little water as the water sloshes around in the tank when we are driving. But this would probably not be catastrophic and we would likely notice it happening as we open our sink cabinet just about every day.
In order to reach water at the bottom of the tank from a bulkhead fitting that is installed at the top of the tank, we attached flexible tubing to the FIP connection on the bulkhead fitting on the side in the interior of the tank, as shown in the photo. We discovered after using this system that the flexible tubing does not naturally sit on the bottom of the tank. So we added a stainless steel barb-to-FIP fitting to the end of the flexible tubing to act as a weight and keep the inlet always on the bottom of the tank.
The photos below show the rest of the pumping assembly. Once outside the tank, a male NPT union is used to connect to the pump hose. This hose is recommended by Shurflo as it helps to reduce pump noise compared to rigid PVC. On the other end the hose connects to a pipe strainer, which keeps particles out of the pump. The pipe strainer connects directly to the pump. The pump is manufactured by Shurflo, which seems to be one of the more popular pumps used in campervans and RVs. We have been using it for over a year with no major complaints.
After the pump we have an accumulator that is also made by Shurflo. An accumulator is basically a small tank with a diaphragm that can be pressurized on one side via an air pump. The purpose of the accumulator is to reduce pump cycling and smooth faucet pulses.
Pump line outlet from fresh water tank 
Strainer, pump, and accumulator. 
Interior of sink cabinet showing entire pump system.
Supplying
The accumulator connects to the Filtrete filter system (below left) through a brass ½” FIP to ⅜” compression fitting that connects to ⅜” flexible tubing. This flexible tubing comes with the filter system. Our filter is a 0.5 micron filter that reduces chlorine taste and removes sediment and microbial cysts. We replace the filter every six months. If you plan on drinking the water from your water system, we would highly recommend getting a water filter; water quality at fill stations is highly variable.
To connect the filter to the sink, a ⅜” compression tee is required to split the line into two, as shown in the photo below right. These two lines connect to the hot and cold lines of the faucet through flexible braided hoses. We do not have a hot water heater for our sink; we haven’t really seen a need for it. If we wanted to add a hot water heater, it would be installed between the ⅜” compression tee and the flexible braided hose on the hot water side of the sink.
Filtrete Filter system inside sink cabinet. 
Compression tee that is used to connect to hot and cold lines of sink.
That sums up the fresh water side of our water system. The following section describes the grey water system. Here’s one more photo of the sink, being used by our niece and nephew. Of course they are using it for it’s most common purpose: washing dishes!
Grey Water System
Materials
Materials used in the construction of the grey water system are shown in the table below. The order of the components in the table follows the flow of grey water through the system, starting at the sink and ending at the discharge tubing.
Flow Diagram
The flow diagram below divides the assembly of the grey water system into three categories: draining, storing, and dumping. The items in the diagram are clickable links to product pages. The blue arrows in the diagram indicate the direction of water flow. Application of thread sealant is shown in four areas. The straps are used to secure the grey water tank on the underside of the van. The plugs are used to plug three out of four of the NPT fittings on the side of the tank.
Description
In the following sections we will describe each of the three categories of the grey water system identified in the flow diagram: draining, storing, and dumping of the grey water.
Draining
On the underside of the sink, inside of the sink cabinet, is the plumbing to get the grey water from the sink into the grey water tank. The part just under the sink is called a tailpiece. The next piece is called a p-trap; it is actually composed of two pieces so you can orient it in whatever direction works for your application. The p-trap reduces odors in the sink by creating a j-bend where water is trapped at the bottom of the bend. This water barrier prevents odors from the grey water tank from coming up into the sink. If you travel on a bumpy road and find that your sink is a bit stinky afterwards, likely what has happened is the water in the j-bend has been sloshed around and found its way down the drain piping. Just run the sink for a few seconds to fill the j-bend back up and it’ll help with the smell.
After the p-trap, there is a piece called an elbow extension. This piece goes to a 1-½” adapter to connect to 1-½” schedule 40 PVC. Primer and cement are used to connect the adapter piece to the cement. There is a good article here about how to apply primer and cement if you are unfamiliar. The PVC pipe is secured with a pipe strap to the wood piece in front of the tank, as shown in the photo above.
This PVC goes through the floor of the van into the grey water tank. I drilled a hole through the floor of the van using a 2” diameter hole saw, as shown in the photos below.
Hole drilled in floor for drain line. 
Drain line sticking through hole.
Storing
To hold our grey water, we purchased an 8 gallon holding tank with the standard fittings installed. Choosing the grey water tank was about as difficult as choosing the fresh water tank. The first thing that I did was get underneath the van with a tape measure and measure the constraining dimensions.
Here are some photos from the process below. There is an emergency brake bracket on both sides of the van, even though only one of them is used. Don’t ask me why this is the case. You can see it in the first picture below. I contemplated whether or not to remove it, but I decided it wasn’t worth the hassle. This bracket limits the overall width to 12 inches. The overall length is 20 inches, and the overall height is 10 inches. The height requirement is based off of the location of the rear strut attachment point. In summary, we needed to find a tank with dimensions less than 20”L x 12”W x 10”H. The 8 gallon tank that we decided upon has dimensions of 18”L x 11.5”W x 10”H. It was about the largest that we could fit underneath the van without grinding off that unused emergency brake bracket.
Width between frame support beams. 
Available length between obstructions. 
Height to rear strut attachment point.
In the picture below the tank is held in place with a pneumatic jack. It’s a pretty good fit. The top two fittings are blocked by one of the support beams that make up the frame of the van, but this isn’t really a big deal because we aren’t using them.
With the tank held in place by the jack, I used a permanent marker to outline the location of the hole drilled through the floor of the van on the top of the tank. See the two photos below. I then installed fittings into all four of the standard FIP fitting points on the side of the tank as shown in the bottom right image. Thread sealant was used on all four fittings. Three of the fittings are plugs, and the last one is a 1-½” PVC NPT to socket adapter fitting.
Marking location for inlet hole in grey water tank. 
Grey water tank with location for drain inlet hole marked.
You may be asking at this point why we didn’t leave the small fitting at the top open for venting. Grey water tanks need to have a way to let air in and out near the top of the tank, otherwise they will fill and drain very slowly. In lieu of using the top fitting as a vent, our drain pipe comes into the top of the grey water tank without any sealing between the outer surface of the PVC and the tank. Since the OD of the PVC pipe is 1.9” and the hole that we drilled in the tank is 2”, there is a 0.05” gap between the pipe and the tank. This works very well in allowing air in and out of the tank. It’s possible that a little grey water could leak out, but not very likely. The water would have to splash up right where the 0.05” gap is located. If a little water does spill out it’s not the end of the world; our grey water isn’t that dirty.
We then put the pipe into the sink cabinet to determine how long the drain pipe into the tank needed to be (see top left photo below). We wanted it to stick into the tank 2 inches. After cutting the pipe and cementing on the adapter fitting we installed the pipe into the sink cabinet (see top right photo below). The PVC pipe sticks below the van by 2 inches (see bottom photo below).
Placing PVC in order to determine length to cut. 
PVC cut to fit and adapter installed. 
Drain line seen from below before installing tank.
After getting the PVC pipe in place we also sealed it with caulk on both sides as shown in the photos below. Make sure to clean the area around where you will be caulking before applying it or it will not stick well. We generally use vinegar to clean and then dry thoroughly before applying.
Caulk applied around exterior of PVC drain pipe underneath van. 
Caulk applied around exterior of PVC drain pipe in sink cabinet.
We wanted some protection between the plastic tank and the metal on the underside of the van because this seems like an area with a potential to rub. To provide this protection we used aluminum waterproofing tape. This stuff is used in a lot of different applications, mainly to seal and repair leaks. It is composed of a rubberized asphalt adhesive with an aluminum backing. We covered the top of the tank with the tape, and put two strips along the bottom where the straps hold the tank in place.
To hold the grey water tank in place we used metal straps underneath the tank that are screwed into the body of the van on two separate crossbeams. The steps involved are as follows:
- The first step was to figure out where to bend the metal bars.
- To do this I put the tank in position using the pneumatic jack, as shown in the left photo below. Then I took masking tape and ran the tape in the exact locations where I wanted the straps to be. Make sure to clean the van frame members where the tape needs to go or else it will get dirty and not stick in place.
- After placing the tape, I used a permanent marker to mark on the tape at each bend location. Then I removed the tape and taped it directly to the metal bars (see photo below right). I labeled the straps “edge” and “middle” so I wouldn’t lose track of which one was closer to the edge of the van and which one was near the middle of the van.
- With the tape as a guide, I placed the strap into a bench vise at each of the bend locations and hit it with a hammer to make the bends. To get the bends right was a bit of guess and check. I would bend it until it seemed right, then take it out of the vise, and go check it underneath the van while the tank was still held in place.
Tanked held in place by pneumatic jack. 
Guide tapes applied on metal straps.
- To hang the straps, we used self-drilling #14 x ¾” hex head screws. Below left shows me under the van drilling in the screws; it is a tight squeeze. Below right shows the tank secured in place. I tested the snugness of the fit by trying to get the tank to move; it wouldn’t budge in any direction. There’s a little bit of a gap visible between the straps and the bottom of the tank; this is because the bottom surface of the plastic tank is slightly concave. I don’t know if this is intentional in the design, but it could be done that way so that it flattens out as the tank is filled with water.
Drilling self-tapping screws into frame member to secure straps. 
Tank secured to bottom of van with metal straps.
Dumping
The dump line is fairly straightforward once you understand the basics of connecting PVC with primer and cement. The PVC used for the dump line is all cut from the same 5-ft 1-½” PVC pipe that was also used for the drain line into the grey water tank. In the previous section, I showed the installation of the 1-½” PVC NPT to socket adapter fitting using thread sealant to the 1-½” FIP connector on the side of the grey water tank. A separate flow diagram just for the dumping portion of our water system is shown below to make clearer how everything is connected. Once again in this diagram, you can click on individual components to be taken to the product page.
The image below shows the entirety of the dump system. After the socket adapter, there is a short piece of PVC that is primed and glued into the socket adapter on one side and into the ball valve on the other side. You can get cheaper ball valves at hardware stores, but I decided to spend a bit more on this one. It’s a lot easier to open and close, and it is a union ball valve so it can easily be removed if there is a problem. After the valve is another short piece of PVC, followed by a coupling union. This coupling union is supported by a 2” pipe hanger that is screwed into the underside of the van, as shown in the photo below.
Following the coupling union is a reducing bushing from 1-½” PVC to 1” PVC. The last piece in this assembly is the 6-ft flexible discharge tubing. This piece fits snugly into the end of the reducing bushing. When draining the grey water, we attach the discharge tubing to the bushing, put the other end into the dump drain, and open the ball valve. Even though the discharge tubing is not sealed to the bushing, it does not leak when draining the grey water. Below is a photo of the discharge tubing being attached to the end of the bushing.
Final Thoughts
With the new system we have found a significant reduction in the effort and time required to dump and fill our water. With our old water system we generally needed about 20 minutes to dump the grey water and refill the two fresh water jerry cans. Now, the whole process takes less than 5 minutes. It’s also much easier because we don’t have to lift 50 pound tanks of water multiple times.
We have been checking on the undermounted grey water tank when we dump just to make sure it isn’t getting loose; so far it has remained very snug. There has also been a significant improvement in smell. With the old system having the grey water tank inside the van, we would sometimes smell the grey water, especially when opening the sink cabinet. Now, we hardly have any odor at all.
Please reach out if you have any questions. The best way to reach us is via DM on Instagram, @dolly.the.rambler. You can also leave a comment below.
