Sunday, December 4, 2022


Ask Dave: When water pressure is low, will pressure regulator further reduce it?


Dear Dave,
I have a RV water pressure regulator with a gauge. As the output pressure is fixed at the factory, I am confident the gauge is telling me what the input pressure is (red [high], green [good] or yellow [low]). Sometimes the gauge is telling me the pressure is low. Here is my question: When the input pressure is low, does the regulator further reduce the pressure within my RV’s water system? —Jim

Dear Jim,
Since you did not provide the make, model, and year of your RV I cannot look at the spec’s to find out if your water pressure regulator was a standard feature and what model it is. Most RV manufacturers do not have a pressure regulator standard. Rather, there’s a check valve in the city water fill outlet to keep water from flowing back out when using the onboard water pump.

The unit you described is similar to the Camco version that is available almost anywhere RV accessories are sold.

How a pressure regulator works

According to the Camco features it is preset at 40-50 psi and is not adjustable. Inside the valve body is a square plug that I would assume is sized to only allow 50 psi max through it.

Then on the other side, the valve has a port that the water pressure will push on and move the gauge. It is factory preset to 40-50 psi so when it is at 40 psi, the needle would be in the start of the green. If the water is above 50 psi, it is throttle down, so to speak, but pushes the needle into the red. I do not see any way this type of valve would restrict water flow below 40 psi.

However, these can get calcium, lime, and rust buildup and will restrict the water flow as they are blocking the opening around the square insert. To verify pressure, I carry a water tester that just screws on to the end of the water supply and shows pressure without anything going through it.

This will help verify what pressure the source is providing and if your reducer is getting clogged.

I also soak my pressure reducer in some CLR (Calcium, Lime & Rust Remover) periodically and am amazed at how much white “junk” comes out.

 You might also enjoy this from Dave 

What water pressure should I have at the campground?

Dear Dave,
When at a campground, what is the suggested psi setting for an adjustable water pressure regulator? —Tony, 2003 Holiday Rambler Vacationer

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


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Seann Fox
1 month ago

When your campground water pressure is low fill your fresh water tank and use your pump in conjunction with your city water.

Tommy Molnar
1 month ago
Reply to  Seann Fox

Or just use your onboard water – period. We do this often because our water pump provides more water pressure than the park.

Leonard Rempel
1 month ago
Reply to  Tommy Molnar

We have started to do this now as well since we replaced our onboard pump with a super quiet one with an accumulator tank. When we leave for even an hour or two we always turn off the pump, just in case one of the pipes leaks or comes loose. These are all poorly built RV’s as we all know!

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