RV Water Pressure Regulator: The Cheap One Wins

An RV water pressure regulator is a brass fitting that screws onto the campground spigot and costs less than dinner out. It is the cheapest insurance on your trailer, and almost everything written about it gets the main question backward.

Everywhere you look, you are told the cheap ones slow the water down so much you cannot take a decent shower, and that the answer is to spend five times as much on an adjustable one with a gauge.

Winnebago actually tested them. They hooked each one to the same spigot and timed how long it took to fill a five gallon jug. The seventeen dollar brass regulator moved about twenty percent more water than the adjustable one that cost five times the price.

Here is what the numbers actually say, what you are really protecting, and how to pick one.

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What You Are Actually Protecting

Ask why you need a regulator, and most articles say it protects your water lines. That is the wrong answer, and it makes the whole thing sound optional.

The water lines in a modern trailer are PEX, and PEX is rated to around 160 psi at room temperature. No campground is going to hurt it. If PEX were the weak point, you could skip the regulator entirely.

The weak points are everything joining the PEX together. The crimp rings, the plastic compression fittings, the little flexible supply lines under the sink and behind the toilet. RV technician Dave Solberg puts plastic compression fittings at around 60 psi when they are installed properly, and points out that on a new trailer the crimps are not always done properly in the first place.

He has also seen water lines held on with ordinary screwdriver tightened hose clamps come apart at well under 40 psi.

So the regulator is not protecting the pipe. It is protecting the three dollar connection behind a wall panel that you will not find until the floor is soaked.

And the pressure is real. Winnebago measured 115 psi at a test spigot. Mortons on the Move measured 120. That is double what your fittings are rated for, sitting there all night while you sleep.

How Much Pressure Is Safe

Here is where we part company with most of the internet. You will read 40 to 60 psi everywhere, stated as fact, with no source attached.

The rules that govern how RVs are plumbed live in NFPA 1192, and that document is behind a paywall. We do not have a copy, so we are not going to tell you it says a number. Anybody quoting you a specific figure from NFPA 1192 without owning it is guessing.

What we can tell you is what the manufacturers themselves print, which is better evidence anyway.

• Winnebago says a regulator should hold pressure to 50 psi maximum.
• Valterra prints on its own product page that settings above 60 psi are not recommended, and to check your RV manual.
• Camco presets its regulators to 40 to 50 psi and leaves it there.

Three manufacturers, no coordination, and they land in the same place. Set yours around 45 to 50 and stop thinking about it. If your trailer came with a manual that gives a number, that number wins.

The Flow Rate Myth

This is the reason most people spend the extra thirty dollars, and it does not hold up.

The story goes that a cheap non-adjustable regulator strangles your water, so you need an adjustable one to get a decent shower. Winnebago tested it properly. They ran an unregulated spigot at 115 psi as a baseline, which gave 17.2 gallons a minute, then timed a five gallon fill through each regulator.

The results, in gallons per minute:

• Valterra stainless high flow, not adjustable: 10.4
• Camco 40055 brass, not adjustable, about seventeen dollars: 9.2
• Valterra brass, not adjustable: 9.1
• Watts LF263A, adjustable with a gauge, roughly five times the price: 7.7, the worst of the group

The expensive adjustable one came last. Winnebago also found its built-in gauge was inaccurate and that it was awkward to adjust.

Why the expensive one flowed the least

So we looked up Watts’ own paperwork, and it explains the whole thing.

The Watts is not an RV part at all. Watts sells it for beverage machines, ice makers, paint spraying, humidifiers and drinking fountains. It is only built with half inch openings or smaller, and Watts’ own figures say it will carry no more than 7 gallons a minute.

Your hose and your trailer’s inlet are three quarter inch. The RV sellers take that smaller valve and screw hose fittings onto each end so it will connect up. The narrow part in the middle stays narrow. It was never built to carry as much water as a campground hookup can push through it.

And none of it matters much anyway

An RV showerhead uses about 2 gallons a minute. Every regulator in that test delivered between 7.7 and 10.4. You are not going to notice the difference in the shower, because the showerhead is the restriction, not the regulator.

So when somebody genuinely does lose water pressure after fitting a regulator, the regulator design is usually not the cause. See the next section.

When the Flow Really Does Drop

Most regulators have a small screened washer in the inlet. Renator and Valterra both ship one. It catches grit before it reaches the diaphragm inside.

That screen clogs. Campground water carries sand, rust flakes and bits of the last person’s hose washer, and a screen the size of a dime fills up quickly. When somebody says a regulator killed their shower, this is nearly always what happened.

The fix takes two minutes and no tools beyond a pair of pliers. Unscrew the regulator, look into the inlet end, and pick the screen out with a fingernail or the corner of a knife. Rinse it, look at it against the light, and put it back the same way round. Do it at the start of the season and any time the pressure drops off.

If the screen is clean and the flow is still poor, then you have a regulator that is failing rather than one that is blocked.

Three Regulators Worth Buying

Prices move, so check before you order. All three are currently available.

The Lead Question, and a Surprise

This is drinking water going through a brass fitting, so lead is a fair thing to ask about.

There is a real federal rule. The Reduction of Lead in Drinking Water Act took effect in 2014 and amended the Safe Drinking Water Act. Lead free means a weighted average of no more than 0.25 percent lead across the surfaces that touch the water. NSF/ANSI 372 is the standard used to certify that a part meets it.

Here is the surprise. The seventeen dollar Camco is the one an outside body actually checked. Its listing says CSA certified it to that standard.

The fifty dollar Renator gives you its own number instead. It says the brass is under 0.13 percent lead, which is well inside the limit, but nobody outside the company is named as having checked it, and Renator will only send you the test paperwork if you email and ask for it. The Valterra simply says lead free, with no standard and no certifier mentioned anywhere.

Say this carefully, because it matters. A missing certification is not evidence of lead. It is evidence of a claim nobody else has checked. All of these are sold as lead free and probably are. But if a documented certification is what you want, the cheapest one is the one that has it, which is the reverse of how this usually goes.

Where to Put It

On the spigot, before the hose. Not at the trailer.

The reason is the hose. If the regulator is at the trailer end, the hose spends all day holding whatever the campground is putting out. One owner on the Forest River forum described coming back to a hose that had swollen, in his words, to the size of a summer sausage. Hoses left pressurized in the sun do burst, and a burst hose at a full hookup runs until somebody notices.

There is a counter argument that mounting at the trailer avoids losing pressure down the length of the hose. Somebody did the arithmetic on that: a 25 foot, five eighths inch hose flowing 2 gallons a minute loses about a quarter of one psi. It is a real effect and it is far too small to care about.

So put the regulator on the spigot, then the hose, then the trailer. The one exception worth knowing is if you are on a well or a system that already runs under 50 psi, where you want every bit of flow you can get.

Regulator or Filter First

Regulator first, then filter, then the hose to the trailer.

The reason is that filter housings are plastic, and on that whole run they are the part least able to take pressure. Putting the regulator ahead of the filter protects the housing along with everything downstream of it. Turn it around and you have a plastic canister sitting at full campground pressure.

The one time to reverse it is genuinely low supply pressure, where the filter first costs you less flow. On a normal hookup, regulator first, every time.

How These Fail

The important one first.

It fails open

A regulator that quits usually quits by passing everything straight through. It looks identical from the outside, it feels the same in your hand, and the first sign is often a wet floor. This is the whole argument for a gauge. A regulator with no gauge that has failed open is indistinguishable from one that is working.

The pressure drifts

Fixed regulators wander a little as they age. Adjustable ones have more moving parts, and more parts means more ways to drift. If you have a gauge, glance at it now and then rather than assuming the number you set last spring is still the number.

The inlet screen clogs

Covered above. Most common by a distance, and the easiest to fix.

Grit reaches the diaphragm

If the screen has been missing or damaged, sediment gets to the rubber diaphragm inside and the regulator starts restricting flow for real. At that point it is a replacement, not a repair. At seventeen dollars that is not a hardship.

Two honest gaps. We could find no manufacturer failure data, no warranty claim rates, and no published testing on how long these last. And we found no recall, from CPSC or any manufacturer, for any RV water pressure regulator.

Do Not Use a Garden Regulator

Irrigation regulators look similar, cost about the same and are sold in the same aisle. They do not work for this.

Winnebago tested one, a Dig unit marked 25 psi. Fed with 115 psi it passed 82 psi straight through. Winnebago called it nearly worthless, and that is fair. These are designed to regulate at the steady high flow a sprinkler line draws, and an RV draws small amounts intermittently. At the flows you actually use, it barely regulates at all.

Buy one sold for RV or marine use.

Common Questions

Do I really need an RV water pressure regulator?

Yes, and it is the cheapest protection you can buy for a trailer. Campground spigots have been measured at 115 and 120 psi. The plastic fittings inside your walls start letting go around 60, and some fail well below 40.

What psi should I set it to?

Around 45 to 50. Winnebago says hold it to 50 maximum, Valterra says do not go above 60, Camco presets to 40 to 50. If your trailer manual gives a figure, use that instead.

Will a regulator ruin my water pressure?

No. In the only published test we could find, every regulator delivered between 7.7 and 10.4 gallons a minute, and a showerhead uses about 2. If your flow drops after fitting one, check the inlet screen for grit.

Is an adjustable regulator better than a fixed one?

Not for flow, and not for price. The value of an adjustable one is the gauge, which is the only way to notice that the regulator has failed open. If you buy a fixed one, buy a good one and replace it every few seasons.

Should it go on the spigot or on the trailer?

The spigot. That way the hose is protected too, and a hose left at full pressure in the sun is a real way to come back to a flooded site.

Do I need a filter as well?

That is a separate job. A regulator controls pressure and a filter controls what is in the water. If you use both, the regulator goes first so the plastic filter housing is not sitting at full pressure.

Can I leave it on all winter?

Take it off and bring it inside with the hose. Water trapped in the body freezes and can crack it, and it costs nothing to unscrew.

The Short Version

• The regulator is protecting your fittings and supply lines, not the PEX. PEX handles 160 psi. The plastic fittings start going at 60.
• Set it around 45 to 50 psi, or whatever your trailer manual says.
• The cheap non adjustable brass one out flowed the expensive adjustable one in the only real test published. Ignore the flow rate argument.
• Buy an adjustable one for the gauge, not the adjustment. Regulators fail open and silently, and the gauge is how you find out.
• Never buy an irrigation regulator. One tested at 25 psi passed 82.
• Fit it on the spigot, before the hose, and put the filter after it.
• If flow drops, pull the inlet screen and rinse it before you blame the regulator.
• Take it off and bring it indoors before the first freeze.

Related Guides

• Water leak detectors for travel trailers
• Freeze alarms for a winterized RV
• RV storage security, the complete guide
• RV water filters, the filter goes behind the regulator, and its housing is the pressure weak point.