So I have a small class C that I really intend to just use at camp sites. So the water pump will not be needed most of the time. I really only need it to flush the toilet on trips (I think... I have never actually been in an rv before).My question is.. if I get a well reviewed 1.2GPM pump off Amazon... Will it be enough to flush the toilet? Also, on the off chance that I want to shower... Will it be TERRIBLE or tolerable. I read that a house shower only uses 2.3GPM so I figure it should be like a weak shower. I am OK with that as I would just be using it in extreme cases. I figure experience is kind and want to make sure this is not a STUPID idea. Again... I am OK with low pressure for the shower as long as it will at least work? But the main thing is to flush the toilet. :)

Well, you are partially correct. Just because the pump can pump 3 GPM, or 1.2 GPM is only half the factor. The other half is how big in diameter the water lines are in the camper. Smaller lines will flow less water. So even though a pump may be capable of 1.2 GPM, the lines might be so small it only pumps 1/2 GPM. Shower head almost always water saver reducers built into them to prevent the maximum flow, even possible with a 1/2 inch diameter pipe with water behind it. The actual opening in that shower head may be 1/8 inch, restricting the amount of water that can pass through, thus taking longer to run that 1.2 gallons. Your toilet just flows water. Whatever the valves the water has to pass through are set for, will really determine how much (or how fast) the water will flow (regardless of pump size).So actually, taking a shower, you'll probably not see any difference between a 1.2 or a 3.0, because of the shower head restricting flow. Same is true for the toilet.Now, if all your water lines are 1/2 inch (which most are in RV's), you may notice a difference in output at the kitchen sink, as kitchen faucets usually have no restrictions (although some of the newer ones do).Hope this helps.

Dutch is correct, and I might add the pump pressure is more important than volume in being able to overcome the restrictions. 60psi is too much, and 35 is about right. I wouldn't go lower.

If you are looking at the ones, for about $29, it does have much pressure. It is only rated at 35 pounds.you would be better off with one that is around 50 PSI output.Yes, it is a little more money, but you would be happier!

OK, My question to your question, Why are you looking at a pump on Amazon, does your Class C not already have a pump?I don't know about GPM, flow rate, pipe sizes and all those technicalities, but I do know that we have taken many, many showers in our class c and had no problem with pressure. As far as enough pressure to flush the toilet, that is a Non Issue, as you simply lift the pedal till the bowl get to the needed level, then push the pedal down, WOOSH.

1.2 GPM is enough to fill up the toilet and flush it, but to give the bowl a good rinse as it might need at times it takes water flow. 1.2 doesn't sound like much at all. Another factor is the pressure at which the flow is rated. 1.2 GPM at 50 psi might provide adequate performance but the same flow at 10 psi certainly will not. You literally won't get much more than a dribble out your shower head. Personally, I'd spend a few bucks more and get a pump designed and specced specifically for RV use.

Water pump question GPM? | Good Sam Community

enblethen
Nomad
Jun 22, 2017
If you are looking at the ones, for about $29, it does have much pressure. It is only rated at 35 pounds.
you would be better off with one that is around 50 PSI output.
Yes, it is a little more money, but you would be happier!
2oldman
Explorer II
Jun 22, 2017
Dutch is correct, and I might add the pump pressure is more important than volume in being able to overcome the restrictions.

60psi is too much, and 35 is about right. I wouldn't go lower.
DutchmenSport
Explorer
Jun 22, 2017
Well, you are partially correct. Just because the pump can pump 3 GPM, or 1.2 GPM is only half the factor. The other half is how big in diameter the water lines are in the camper. Smaller lines will flow less water. So even though a pump may be capable of 1.2 GPM, the lines might be so small it only pumps 1/2 GPM.

Shower head almost always water saver reducers built into them to prevent the maximum flow, even possible with a 1/2 inch diameter pipe with water behind it. The actual opening in that shower head may be 1/8 inch, restricting the amount of water that can pass through, thus taking longer to run that 1.2 gallons.

Your toilet just flows water. Whatever the valves the water has to pass through are set for, will really determine how much (or how fast) the water will flow (regardless of pump size).

So actually, taking a shower, you'll probably not see any difference between a 1.2 or a 3.0, because of the shower head restricting flow. Same is true for the toilet.

Now, if all your water lines are 1/2 inch (which most are in RV's), you may notice a difference in output at the kitchen sink, as kitchen faucets usually have no restrictions (although some of the newer ones do).

Hope this helps.

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