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I based my campervan water system design on my needs and a few nice to haves too. Planning to live in the camper van long term, I didn’t want to scrimp on the set up.
I wanted enough fresh water to last 2 of us at least 5 days off grid, shower facilities and the ability to cope with dubious water sources.
This post sets out my campervan water system design. It’s pretty generic and aside from sizing and component specifics, is what most motorhome, RVs and camper vans have installed.
The Bush Ranger shower is a little different though. If you’re looking for a design for your own van build, this is a great base to start from.
If you’re new to the world of self build camper vans and don’t know where to start, here’s everything you need to know about a camper water system before you start.
It explains all the basics and will help you size your system before getting to the nitty gritty of design.
Campervan water system design
The rest of this article provides my campervan water system design in the following sections:
- An overview of the campervan water system design
- Fitting the water tanks
- Detailed design of the cold water system
- Detailed design of the hot water system & how we heat water
- An overview of the Bushranger outdoor shower
- Monitoring and system controls
- Electrical connections for a camper van water system
- Component list
- Tools list
An overview of my camper van water system design
The diagram above outlines my camper van water system design.
I based the amount of water I need on the sizing calculations explained here. For both us to to survive off grid for upto 5 days we need 125 litres. I managed to fit 3 water storage tanks to give me 170 litres so I have extra contingency too.
The water heats as it passes through the engine coolant as the engine is running. I can use 12v to run the immersion too but only use this if I’m on shoreline hook up so it doesn’t kill my batteries.
The water pump feeds both hot and cold water to the kitchen sink and the outdoor shower. It supplies cold water to the ceramic filter to provide clean drinking water too.
We avoided submersible pumps. I mounted the Shurflo water pump under the kitchen sink for easy access. With a micro switch fitted, it maintains constant pressure of running water.
To monitor the water level, I fitted a water gauge at the side of the driver’s seat. With the press of a button, I can see how full (or empty) my tanks are.
As a late addition to the system, I also fitted a Bushranger shower. It doesn’t use any water from the onboard supply; rather from an external source such as a river of lake. I explain this in more detail below.
Fitting the water tanks
A litre of water weighs 1 kg and takes up 10 cubic centimetres. For my 170 litres then, I was adding 170 kg of weight to the van plus the weight of the tanks and I needed to find 0.17 cubic metres to store the tanks.
I could have stored some, if not all the tanks inside the van but this would use valuable storage space. I’m not aiming to winterise the van so I decided to hang the tanks underneath.
Finding the space to fit water tanks
There’s only so many places underneath any van to attach water tanks. On our Sprinter van, once I discount the space for an engine, 4×4 gear box, exhaust system, brake lines and cable runs, existing fuel tanks, chassis rails and cross members there isn’t much space to work with.
And I still needed to fit a hot water heat exchanger, an extra fuel tank and a grey water tank.
Weight and load balance is also a significant factor to consider. I need to keep as much load low down and between the axles. If you don’t understand why, read my post on overland build and vehicle modifications.
I also considered the exit angles of the camper van and needed to ensure the side of tanks didn’t break the main body lines, so not impinging on the ground clearance.
Spending hours on my back underneath the van, I measured and remeasured, trying to find the space I needed. I moved the spare wheel carrier to the rear door to give me a little extra room to play with.
Each potential designs I came up with, off the shelf tanks in the sizes I needed weren’t available.
I could have gone with bespoke made tanks. Stainless steel was out of my price range. Even the custom made black plastic tanks were expensive. Eventually, I came up with a design.
I made some considered compromises in respect of the location and used standard size tanks.
I also had to consider how water would flow from the main fill to the fresh water tanks and how the sink drain would flow to the grey water tank.
Words of caution
Even with careful measurements it took me 3 attempts to find a tank that fitted. Once, a chassis rail “magically” appeared in an unhelpful location.
On the second attempt, the manufacturer produced a tank with a large tolerance. Somehow 800mm came in as 830mm long.
Here’s the layout of the underneath of my camper van, a right hand drive T1n1 4×4 Sprinter van with dual rear wheels. It’s a bird’s eye view looking down on the van.
The final set up
I’ve fitted 2 water tanks. Tank 1 is 700mm x 350mm x300mm and fitted between the chassis rail and the body on the driver’s side. I positions the fill cap fitted to the outside of the panel.
Tank 2 is the largest tank at 500mm x 250mm x 600mm, fitted close behind the rear axle.
The 20 litre hot water tank outside dimensions are 300mm x 300mm x 400mm and the grey water tank is 300mm x 300mm x 500mm.
I fitted both between the chassis rail and the body of the van. To avoid the need for transfer pumps, gravity feed tank 2 from tank 1.
A 50mm wide flat bar secures the tanks to strong points on the chassis and inner body panels.
Where possible, I drilled and tapped M10 bolts into the chassis, or screwed to the floor pan for extra support. I secured Tank 2 with added cross members and threaded bar hangers.
Pushing the hoses between each tank on to the connector and sealing them with jubilee clips, secured them in place. I routed and secured the hoses along the chassis and flooring by P clips.
So far, the design is working perfectly, even on sought tracks in Paraguay, Bolivia and Patagonia. Let’s hope it copes well in the Brazilian rainforest!
Detailed design of the cold water system
The cold water system is the simplest part of a fitted camper van water system.
Filling & pumping
The fill cap is on the driver’s side and this allows water to fill tank No 1. I’ve fitted a 25mm balance line from the base of this tank to gravity fill fresh water tank No 2.
I installed the water level monitoring on tank 2 because it’s lower than tank 1. If I need to empty the entire system for winter storage or maintenance, I can use the drain valve fitted to tank 2.
The balance line between the 2 fresh water tanks needs to kept in line with the body sills so they don’t drag or get caught on anything.
This isn’t a problem unless you have a hot exhaust pipe in the way. After a slight balance pipe malfunction due to it falling onto the hot exhaust pipe, and melting a hole, I replaced this section with a metal pipe and secured the hose with P clips.
I fitted a Surflow 12v water pump to tank 2. Because this 30 psi pump can draw water to a height of 5m, I didn’t need to worry about how I routed the pipes around the underside of the van.
Water filter & grey tank
The water pump has a course filter fitted to protect the pump if any debris falls into the water tanks during filling. Cold water is drawn by the pump to the hot and cold mixer tap at the sink, the hot water heat exchanger, the shower and the water filter.
The water filter is supplied with its own connectors, micro hoses, isolating valve and faucet. By switching off the isolating valve, I can clean or replace the ceramic filter without draining the entire water system.
I’ve fitted a grey water tank attached to the drain pipe from the sink. I decided against an internal shower so I’ve not fitted a drain in the bathroom.
I’m happy with the outdoor shower for the time being but if I change my mind in the future, it’s easy enough to waterproof the room and add a drain.
Detailed design of the hot water system
In theory, I could have gone without hot water but it makes for a less than pleasant showering experience so put this down as a bad idea. I’ve 3 ways to heat water: a hot water coalescer, a 12v water heater and Bush Ranger shower unit.
Hot water coalescer
In simple terms, cold water is pumped into the hot water tank from the main tanks until full.
As the engine runs, engine coolant is passed through a copper coil inside the hot water tank, so transferring heat to the cold water. It takes about 30 minutes to get a full 20 litres of hot water.
Once the engine has stopped any hot water used is replenished by cold water and the temperature can rapidly drop. This demands we get into good habits of when to shower so we can both have enough hot water.
Note: when the tanks are dry, I need to fill the cold water tanks then switch my pump on to fill the empty hot water tank.
12v hot water heater
The hot water tank I’ve installed also has an inbuilt 12v water heater. It’s heavy on batteries (about 17 amps per hour) so I’ll only ever use it when hooked up to shoreline power.
Bush Ranger Shower
It seems the Australians have a very macho idea that overlanders need to shower every day regardless of the terrain.
We discovered this clever device in northern Africa while camping next to a camel’s watering hole.
As we stopped for the night to camp, up pops the bonnet of a defender and out pops a tall slim Australian germanic chap and his dainty wife in their swimming costumes.
He throws a hose into the well and they showered away the grime, dust and heat of tough days driving in the Sahara desert. Giggles abound, bloody brilliant gadget! So we had to get one for a Baloo.
The Bush ranger shower is also heated by running the engine to provide heat to its heat exchanger via the engine coolant.
It is easy to install by redirecting the engine cooling pipes to flow through this heat exchanger.
Instead of using our onboard water, another 30 psi water pump is fitted to draw water through a fine filter from a river, well, lake or bucket of cold water and pump it through the heat exchanger.
Now we can shower without depleting our drinking water or for as long as the river is full!
Bullfinch shower unit
The design choice to fit the shower for outdoor use rather than in a dedicated wet room, meant installing it at the rear doors. We can hang a shower curtain at the back door and shower even in less remote areas.
The bullfinch unit incorporates an integral connector to both the hot and cold water supplies. Bearing in mind how quickly the heat exchanger can loose warmth, we can both have a couple of quick showers, at the end of a drive.
Monitoring and system controls
I fitted a water gauge to tank No 2 because it’s balanced with tank No 1. With the gauge located at the base of the driver’s seat it’s easy to check daily. It’s not a completely accurate reading but gives a good approximation of available water.
Electrical connections for campervan water system
My camper van water design does need several 12v power supplies, mainly for the water pump, gauge and 12v heater.
Mixing water and electrics can be dangerous to life so if you’re not sure what you are doing, you might want to outsource this part of your build. You might want to take a look at our electrical design document for more information.
Read more: camper van electrical design
Components used on the camper van water system
You can find most of the plumbing components I used on the high street or the internet.
- Water filler and lockable cap
- CAK water tanks
- Surflow water pump
- 20 litre hot water tank Nautic-Therm Standing 12v 200w ME by Ealgna in Germany
- 1/2″ (12mm) red and black reinforced hot water hose
- 12mm T Piece Connectors
- 12mm and 25mm Jubilee clips
- 1” ( 25mm) Reinforced water fill hose
- 19mm coolant system reinforced oil and petrol hose
- Mixer tap
- Doulton water filter
- Bullfinch external shower point
- Engine bay shower from Bush Ranger, Australia
- Shower head, shower hoses and hose connectors
- Flat store water hoses
- Garden hose connectors
- Magnet base and shower hose holder
I didn’t use many specialised tools to install the water and plumbing in the camper van. If you plan to install the water system in your camper van yourself, you’ll need at least these tools:
- Tape measure
- A drill
- Spanners, bolts and angle iron for hanger bolts
- Sharp knife
- 7mm socket for jubilee clips
- PTFE plumbers tape for joints.
- Kettle to heat tight fitting hose pipes and to make tea
- Some old rags for mopping up
This camper van water design meets my specific needs. Your own may be similar, or a world apart. Still the basic plumbing and heating principles are fundamentally the same.
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