Most van conversions will want to have some kind of system to provide fresh water for washing dishes, cooking, showers, … And, some kind of system to safely and legally handle the water (grey water) that drains from sinks and basins. This section covers a couple options to satisfy these needs.
- 1 Fresh Water System Features
- 2 Grey Water System Features
- 3 How Big Should the Tanks Be?
- 4 Example Systems: Fresh and Grey Water Systems for Our Simple Van Conversion
- 5 Example Systems: A Very Simple Water System
- 6 Traditional RV Water Systems
- 7 Quantity Indicators
- 8 Comments, Questions, Suggestions, Ideas?
Fresh Water System Features
The fresh water system in a camper van or RV is all the stuff needed to deliver fresh water to the kitchen and bathroom for washing, cooking, showering…
A fresh water system will include:
- A means to store fresh water ready for use.
- A means to fill the storage tank
- A means to deliver water from the tank to the points of use (sinks, …)
- Tanks located in the van must be well secured.
- A means to drain the whole system
- A means to protect the system from freezing.
- A means to sanitize the system
Grey Water System Features
Grey water refers to water that has been used for things like washing dishes, cooking, and showering. Toilet water (called black water in RVeze) is not grey water and is typically stored in a black water tank — see the toilet section.
The grey water system includes all the stuff to collect the drain water from sinks and showers and safely store it and dispose of it.
The grey water system includes:
- A means to store grey water
- A means to deliver the grey water from sinks and shower to the grey water storage tank.
- A means to drain the grey water tank
- Tanks located in the van must be well secured.
- A means to protect the system from freezing
Most grey water systems use a tank or closed container to hold the grey water, but the simplest arrangement just allows the grey water to drain into a container placed outside the van on the ground — the container is then drained at an appropriate place as needed.
How Big Should the Tanks Be?
The size of the fresh water tank depends on: 1) how many days you want to be able to go between fills, 2) what water uses you have (drinking, cooking, washing, showers, …), and 3) your habits — that is, how conservative or wasteful you are.
This can cover a huge range. At the extreme low end, for survival, you only need about 0.5 gallons per person per day to drink. At the other end, homeowners average about 50 gallons of water use per person per day not including lawn irrigation. So, your needs will probably fall somewhere between half a gallon a day and 50 gallons per person per day!
As one example, our camper van has a 17 gallon fresh water tank. There are two of us, and we don’t have many water uses. We drink the water, do some cooking, some sponge bath type washing, and minimal dish washing. We don’t have a shower and the toilet is composting, so no shower or toilet flush water. When we are in travel mode, some of our water needs are covered by places we stop.
I will track this more carefully on future trips, but I believe that our 17 gallon tank lasts about 4 days. This would come down to only 2.1 gallons per person per day. This is probably near the bottom of the design range.
To this, you could add:
Showers: A minimal “Navy” shower in which you get wet, turn the water off, soap up all over, then turn the water back on to rinse and all using a low flow shower head can probably be done for about 2 gallons per shower. A normal sort of home shower with a low flow shower head might be about 1.5 gallons per minute for 4 minutes gives 6 gallons. But, its certainly possible to use much more than that.
Toilet flushing: RV toilets don’t usually use a lot of water to flush. One model of Porta-Potties claims 56 flushes from the 4.2 gallon tank — so, 0.075 gallons per flush. On regular RV toilets, its kind of up to you how much water to use per flush, but 0.1 or 0.2 gallons per flush seems about right — so, maybe a gallon per day per person? It is also possible to use grey water for toilet flushing. Some toilets come with a built in tank for flushing.
Larger RVs typically have fresh water tanks in the 40 gallon range.
As an example, if you want to be able to go 4 days between fillups, you have 3 people, you want to have a “Navy” shower every other day, and you have a toilet that uses flush water — then a rough estimate of fresh water tank size is:
- Drinking and minimal dish and person washing (2.1 gal*3 people*4 days) = 25.2 gal
- Toilet flushing (1 gal)*(3 people)*(4 days) = 12 gallons
- Showers (2 gal)*(3 people)*(2 showers in 4 days) = 12 gallons
Totals to 49 gallons — it does add up!
If you want to preserve the capability to do occasional trips in which you will need to supply your own water for a longer period than your tanks are good for, then you can always: 1) carry some extra water in the 5 gallon plastic Jerry cans, or 2) conserve water so you don’t need as much. Or, both. This probably makes more sense than putting in larger than tanks than you really need except on rare occasions.
This is a good set of hints for conserving water when dry camping…
Grey water tanks can typically be somewhat smaller than the fresh water tank in that not all the water you use ends up in the grey water tank — e.g. water for drinking and cooking and toilet flushing.
Example Systems: Fresh and Grey Water Systems for Our Simple Van Conversion
We have a simple fresh water system that consists of a 17 gallon polyethylene tank housed in the passenger side bed platform. The tanks come in a wide selection of sizes, so it is usually possible to fit your space. A single PEX pipe line runs from the tank to the galley sink, which is the only water using utensil in the van. Water is pumped from the tank to the sink using a 12 volt DC pump that is made specifically for this purpose. The pump turns on automatically when a faucet is opened, and runs until the faucet is closed. These pumps have been used for years in RVs and while they could be a bit problematic years ago, our new Shurflo 408 works very well.
In our system, the tank fill system is very simple. The forward right corner of the tank is right at the van sliding door, and the fill plug is located right at the corner. So, to fill, the fill plug is unscrewed and a garden hose is inserted directly into the tank via the sliding door opening, and the tank filled. The fill plug has a small hole drilled in it to vent the tank. Most RVs have a fill fitting on the outside of the van that goes through the van wall and is piped to the tank.
The system has a drain near the tank. You open the drain valve, and the water in the tank and the plumbing drains out via a pipe through the floor. For freeze protection, we also disconnect the flex hoses going to the pump and allow the water in the pump to drain out. This arrangement drains the system well enough that no antifreeze is needed for winterizing.
There is no indicator or meter to tell you how full the tank is, but its easy to directly observe the water level through the translucent tank wall.
The left pictures show the polyethylene tank and pump. The tank is housed in the driver side bed platform, which is bolted through the floor to keep the tank in place in case of a crash. The fill port is visible on the upper back right corner — to fill, just unscrew the plug and fill tank with a garden hose. The pump is a Shourflo 408 with the recommended set of flex hoses to reduce pump noise. The single red pex plumbing line crosses the van under the finished floor to service the sink on the other side.
The right pictures show the stainless steel sink, which is a sold for RVs and also for use as a bar sink.
Based on a couple trips, the fresh water system has worked well. Given that we don’t have a shower, and that our composting toilet does not use water for flushing, the 17 gallons lasts us quite a while.
At some point in the distant future, we may add a small water heater, but not really missing it for now.
Our grey water system consists of an 11 gallon tank mounted under the floor of the van using straps. The inlet from the galley sink comes in near the top of the inboard side of the tank. The drain plumbing from the sink to the tank is just ordinary PVC pipe with a regular household P trap.
The outlet comes out of the tank near the bottom on the outboard side. The outlet has a threaded cap and a ball valve to open for draining. Since the van does not have a black water (toilet) tank, there is no need for the larger RV sewer pipe — I just used 1.5 inch PVC pipe. For draining, a flex hose of the same size goes from the tank drain to the dump drain.
The tank is vented via a small opening and pipe that only goes a few inches upward from the tank. But, grey water tank vents are often run up to through the roof.
The grey water tank is an experiment — it is made from Medium Density Overlay plywood — this is a specialized plywood that is used for highway signs and chemical tanks. I did this because I could not find a tank that fit the space I had well, and because I wanted to see how well the MDO would do — so far, so good 🙂 The tank actually took a pretty good whack with the ground on our last trip due to an error in driving judgement and came through just fine.
The top left picture shows the MDO tank strapped in place under the van. Top right and middle left pictures show the tank outlet and the drain hose. Since only grey water (no black water) is involved, the 1. 5 inch outlet works fine.
The remaining pictures show the PVC drain plumbing from the sink to the grey water tank.
Based on a couple trips, the fresh water system has worked well. Given that we don’t have a shower, and that our composting toilet does not use water for flushing, the 11 gallons of grey water capacity lasts us quite a while.
One thing that I am planning to add is an indicator that tells us when the tank is (say) 3/4 full. Right now, there is no way to know how full it is.
We seriously considered a simpler system (like the one described below). The main factor in not going that way was that the fresh and grey water containers use up a lot of the space in the galley cabinet and we wanted that area for storing food and utensils.
Example Systems: A Very Simple Water System
An even simpler system just uses Jerry can style plastic water containers located right under the sink in the the galley cabinet. The pump can either be a hand powered, or small electric submersible pumps that go right inside the fresh water container. This is a really compact and simple system with no plumbing extending outside the galley cabinet. If more water is needed, and 2nd or 3rd Jerry can can be carried.
The hand pump version of the system is the simplest of all, but the hand pumps can be pretty slow.
Grey water in this system can be a 2nd Jerry can under the sink that is plumbed to the sink drain, or some people have a container or bucket outside the camper on the ground with the sink drain plumbed to it.
Here is an example of this simple system from Steve Vandweller’s blog:
Traditional RV Water Systems
The fresh and grey water systems in larger RVs are similar to the system we have in our van (above), but with some additional features.
Typically there will be more water use locations (e.g. kitchen sink, bathroom sin, shower, …), and a hot water tank to supply hot water.
You may want to add a tank level indicator for your fresh, grey, and black water tanks. There are several technologies.
Old School monitors — the older level monitoring systems use 4 sensors mounted through the tank wall and located at empty, 1/3rd full, 2/3 rds full, and full. They only sense those discrete levels, so you can be at 1/3rd full, take out a pint of water and be at empty (that is, it will read empty at any level from empty up to 32% full). In addition, the sensors are exposed to the tank fluid and may tend to get “cruded” up and become unreliable. KIB is one brand.
Garnet SeeLevel — uses a sensor strip mounted on the outside of the tank to sense level via the density each sensor sees. Requires access to the side of tank to mount sensor strip to tank via adhesive strip. About $240 for 3 tank sensors and panel. Good description.
Electrosense — This unit uses a sensor that mounts in the top of the tank with several rods of various lengths extending down into the tank. These sensors provide six discrete levels of sensing, and the levels are tailored to the type of tank. They claim that the sensors cannot be fouled by their contact with the tank fluid. You have to have access to the top of the tank, and have some vertical clearance above the tank to allow the sensor to be inserted. About $200.
There are others out there — have a Google around.
One thing to keep in mind is that if you can mount your tank in such a way that the side of the tank is visible once you open a cover or door, and the tank is made from the usual translucent plastic, then you will be able to directly see the water level — nothing beats that! Also, if the top of the tank is accessible and has a plug that can be removed, you could just use a dipstick to directly measure the water level.