Dear Dave,
I have been RVing for 35 years via motorhomes and I have always been perplexed by the need to regulate water pressure in the RV. All the units that I have owned have used PEX plumbing, which is identical to the product used in all of the stick-built homes that I have owned. So, why the need to dial down the pressure, which provides the less-than-ideal amount of water coming through the faucets in RVs? This water restriction forces people to buy faucets and shower heads to improve performance and simulate your home experience. —Michael, 2022 Thor Aria 3901
Dear Michael,
According to my math, which is not always the best (just ask Mrs. Rovang, my 6th grade math teacher!), you have been RVing since approximately 1990. Therefore I would believe most or all of your RVs would have used a version of PEX pipe or tubing. PEX stands for “cross-linked polyethylene” and describes a method of manufacturing and materials. There are several different brands, such as Apollo, SharkBite, VEVOR, Plumber’s Choice, Sioux Chief, and many others.
Advantage of PEX tubing
The advantage of PEX tubing is it is flexible so it is easier to install versus copper or even the older 3/8” gray mobile home tubing used up until the early 1990s. It also has a memory and can expand and contract to almost 1.5 times it’s size, so freezing is less of an issue. Trust me, I froze several units solid while training dealers as well as at the annual Winter Dance Party in Clear Lake, Iowa, every February.
According to the www.pexuniverse.com website, 1/2” PEX tubing has a burst rating of only 80 psi at 200 degrees. OK, that’s not natural. But it does also list 160 psi at 74 degrees. So I do not think the PEX tubing is an issue for pressure at any campground or residential connection. However, their charts do specify wall thickness, which could be different between product suppliers. Still, not an issue in my opinion.
So, why the need for a pressure regulator?
Even though the direct runs of water lines can hold pressures up to 160 psi and can freeze solid and not crack, you need to look at the weakest link in any system. In this case it would be the connections and supply lines.
There are basically three types of connections that can be used, the cheapest being a PVC elbow or flare fitting that is tightened with a worm clamp. Depending on the physical ability or strength of the installer, the worm clamp can leak water at the connection well below 40 psi!
A plastic compression fitting at a connection such as a Sealand, Watts, or SharkBite can possibly hold up to 60 psi if it has been installed properly and has not cracked or loosened. Also, the end of the tubing needs to be cut perfectly straight with no gouges.
Two different PEX connections
There are two different PEX connections used in the RV and residential market: the pinch crimp ring and the compression ring, which literally “welds” the plastic connection or ring to the connection. I used this on my last house and it took a special $800 tool and holding the compression for over 30 seconds. I have not seen this used on any RV that I have looked at. Most use a metal pinch clamp that requires a special crimp tool that ratchets to assure the proper pressure applied to the crimp. Look closely at those crimps on new units under the sink cabinet and other places and you will see the tabs are not closed properly and misaligned, so I do not trust them.
Then there are soft lines use for connections to the water pump to reduce thumping noises, and supply lines to the faucets and shower connections. These all are weak links that can not take higher pressure.
I would definitely use a pressure regulator.
You might also enjoy this from Dave
Beware damaging your RV with high water pressure in campgrounds
Dear Dave,
“I just bought my first RV, a Keystone Springdale travel trailer. I’m concerned about the water pressure at campgrounds. I’ve heard horror stories that too much pressure can damage the water system. Are there ways I can keep that from happening? Do I need to be concerned?” —Lana
Watch this short video for Dave’s answer.
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
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A pressure regulator and slightly lower water pressure is sure better than a leak.
True, but the regulated pressure is always undesirable. So we fill our fresh tank at CGs and work off our pump. Much better pressure.
Tommy, you get a gold star! ⭐️ We have marginal water pressure, so this afternoon I switched on the water pump and what a difference! Thanks for the tip! Now, to figure out why my water pressure when on city connection is low…
Could just be overall low pressure. Large RV parks have a lot of units drawing off their water supply.
Another data driven, fact based excellent article from Dave. Need more articles like this and less opinionated ones.
Better safe than sorry.
Thank you, Dave! A couple of years ago and for several weeks I tested the water pressure at our campsites and if it was less than 60 psi (can’t remember, maybe it was 40 psi?), then I did not use a pressure regulator. However, an RV Travel column (reader comment?) informed me that water pressure can change depending on the number of other campers, or time of day, for example. So, I penitently returned to always using a water pressure regulator, and still do. Thanks again for the discussion of RV water system construction and weak points! 🙂 Safe travels! 🙂
The current park was sold and several people have since managed the water system. Based on my regulator’s gauge the pressure can vary within the same hour between 38psi and 60psi (I set the max pressure at 60psi, so maybe park pressure is higher?).
When we first bought this RV, we set it up in south central Texas in early October, but it would sit unoccupied until we returned in December. The RV system was full, but disconnected from the park’s water. The region experienced a freak 72 hour freeze in November. The PEX was fine. But one PVC elbow and the toilet valve were not. We had problems as soon as I connected to the park’s pressurized water.
City water pressure at our homes is usually around 45 psi. Thats why water towers are 100’ high. The weight of the elevated water is .433 psi/ft. From the tower height to the buried main yeilds 45psi. Those at high elevations need booster pumps while those at lower elevations need pressure regulators.
RV sites use pump pressure to accommodate all sites using water. So they can put out a higher pressure when the demand is low. I’ve seen campsites with up to 80psi water pressure which is not good for your RV’s plumbing. A simple regulator adjusted to 40-45psi will simulate your home pressure and offer inexpensive protection.
Our home water pressure fluctuates between 45 to almost 70. A lot depend on the amount of water being drawn from the main. We have a water tower close to our house, but I talked to the water authority about it. It is mainly there as a storage tank in case of a failure upstream.
Normally our water is drawn from a tank about 1/2 mile away and site on top of a hill. Maybe 300 feet above level of our house.
When I my water line replaced, the company put an inline pressure regulator at my meter set to 50 lbs.
The campgrounds should have a regulator on the output of the pump.
I have damaged my fresh water pump twice by connecting to city water without a regulator. The spring on the pressure switch bent each time. There is more at stake than just tubing material and connections.