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This is a concern I see a lot in forums and Facebook pages, and it was a question we had when first deciding on getting an RV. There are (normally) two different ways to use water on your RV, there is a port labeled “City Water” and one labeled “Fresh water.”
City water definition:
Water that is used in your RV by the use of water pressure provided by the city water source.
Fresh water definition:
Water that is held in your fresh water tank that requires your on board water pump to provide pressure to your toilet and sink.
Fresh water
During your trip you have a few ways of both using and storing water in your RV. lets start with fresh water, in your RV you will have some sort of water holding tank, this water is what you will use when you’re not connected to a water source, meaning its an on-board water tank. This tank requires you to have a water pump to deliver the water to your sink, toilet, and shower. When using your stored water you need to be aware a a few things.
- how much water do I have?
- How big is my waste tanks?
- How do I fill it back up?
Lets start with #1 how much water do I have?
In our motor-home we have a 44 gallon fresh water tank that supplies water throughout our RV, this water is pressurized from our on-board water pump, to be honest most water pumps do not provide a high stream of pressure, I would not recommend using multiple water devices at the same time (shower and cleaning the dishes for example)
#2 How big are my waste tanks?
If you are unfamiliar with this term I recommend checking out what is grey water and black water? As in most RVs the grey water tank is much smaller than the fresh water tank, but why? because the combined water capacity of the grey water and black water tank normally exceeds the amount of the fresh water tank.
Example:
fresh water tank = 45 gallons (water available)
Grey tank = 25 gallons (waste water)
Black tank = 25 gallons (waste water)
The assumption here is that you will have enough in the holding tanks if you use an equal amount of water for both black and grey waste, in a perfect world this is great, but in reality you need to make sure you have a way to measure the amount of water that is in your holding tanks.
Deciding on how much water you will need for your RV will vary greatly on how you expect to use the vehicle and the number of people that will be traveling with you. For our family of 5 we decided to go for a little bit larger tank just do to the fact that we will be spending a lot of time on the road and not connected to a dump site or be able to fill up the tank very often, your results will vary.
#3 How to fill it back up
This will vary from RV to RV but with ours we have a separate nozzle that fills the fresh water tank. This is a gravity fed tube that simply fills the tank until full, remember when you are using water that may be used for consumption (boiling water for food for example) make sure you are using both a water filter and a water hose that is made for clean fresh water.
The water filter that we use is a very simple filter that last a long time, but always make sure you use a filter and proper hose when filling your freshwater tank to ensure you have good clean water
City Water
City water is where the pressure from the city provides water through your RV. This is connected directly to your plumbing in your vehicle and does not require your on-board pump to provide water pressure to your system. This connection does not (in most cases) fill your fresh water tank it just supplies water to your vehicle for immediate use, kinda like when you use a a water sprinkler for your lawn.
When using city water it is much simpler because you don’t have to worry about how much water is available and using your stored water is not needed.
BUT just as when filling your fresh water storage you need to make sure your use both the filter and hose combination listed above, additionally you will need to purchase a water pressure regulator like the one below.
The main reason you will need to add a water regulator is because the water that comes from a faucet can have very high pressure coming from it, if you allow this high pressure water to your plumbing in your RV then you may experience failure in the seals and can case very expensive repairs down the road.
This regulator is the one that we use on our motor-home and it has worked great for us, you simply adjust the top screw to allow the correct amount of pressure to the system and let if do the rest, its a set it and forget it product that is chap and can save you thousands.
Each RV requires different operating PSI for the plumbing system, make sure you know how much pressure your system can handle before connecting to any pressurized water source.
now that you know the difference you are ready to go out and explore our great country. Do you have and questions regarding “fresh water and city water?” what topics would you like cleared up, let us know in the comments section below.
Till next time!
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