THE BEST WATER PRESSURE GAUGE: Dry vs Fluid Filled

by Margaret · Published May 18, 2021 · Updated May 20, 2021

**Our honesty policy: This post may contain affiliate links and I may be compensated if you make a purchase at no extra cost to you. Some are, some aren't--I do some comparison shopping. The important thing is you will know exactly what we are talking about. Drop a note/comment if you have any questions on the products as these are materials and tools we use on our own projects.

The quest to find the most functionally economical (works AND cheap) AKA best water pressure gauge!

The quest to find the most functionally economical AKA works AND cheap AKA best water pressure gauge!

What is the best water pressure gauge?

Well, are you like me and you only need it on occasion and none of your neighbors have one?

You just want to check the water pressure on your house or to verify you do–or do not–have a leak?

In this case, IMHO the best water pressure gauge is a cheap fluid filled pressure gauge. We’re going to go over the pros and cons of both kinds of gauges.

TLDR:This is the water pressure gauge I’ve used had planned on using only a couple times, but ended up using constantly for the last 6 months. It literally performed (thanks to overnight Wyze Cam timelapses) without any issues despite the constant sun and UV exposure on this particular hose bibb. Skip to the bottom if you’d like to see this particular water pressure gauge in action.

I went on Amazon–as many of us do–and started doing research. Just $10 gets you a decent list of gauges, but when you start reading the reviews, many of them are…well, cheap.

Now I’m not going to expect a lot from something in that range–you get what you pay for. But I noticed the same problems over and over in the reviews:

It only works once.
It gets filled with water.
It reads wrong.

It seemed like a liquid filled pressure gauge would address some of these problems–or at least have a better chance.

Now I want to clarify. I’m saying “fluid filled” water pressure gauge. Some people say “oil filled.”

They aren’t the same thing, but many times that’s just what it is called. Many are gauges filled with glycerin, occasionally silicone and rarely something else.

Here are the benefits of a Liquid Filled Gauge

The fluid steadies the needle. If you have noise in the line causing vibration, the needle in a dry gauge will bounce erratically making it difficult to pinpoint where the needle is exactly pointing on the gauge
Fluid helps increase the life of a pressure gauge, lubricating the mechanical parts. Here in Arizona that can be a pro or a con. If the vent plug fails, the glycerin will be as hard as a rock in no time!
Related to both those positives, a dry pressure gauge can get stuck and after a 15 minute closed loop pressure test you should be able to tap the gauge to verify the reading is correct. This is less necessary with the fluid lubricating the gauge.

Drawbacks of a Liquid Filled Gauge

Glycerin is temperature sensitive–less than 20 degrees Fahrenheit will start messing with your gauge. If you keep one in place over the summer, make sure to add removing the gauge on your winterization list.
Leakage There is always the risk of a leak.
Temperature changes pressure reading.
Fluid is more susceptible to temperature changes, causing the liquid to expand or contract, which then causes pressure to build up inside the case. While the fluctuation is not very much, it affects the accuracy of the reading. One way to get around this, if you need precision accuracy is to cut the tip off, as recommended, or to prevent leakage, don’t cut the tip and instead, use a screwdriver to let a little air in through the vent plug before each time you use it-essentially recalibrating the gauge.
~~The glycerin can change color–a yellowish tint–darkening over time with UV exposure and temperature changes.~~ Honestly, 6 months after having mine in full sun exposure *in the winter months* the numbers fading from sun exposure is more of a problem than the fluid changing color. You’ll want to angle it or point it down when you aren’t actively looking at it.

Surprisingly, an oil filled gauge still hovers around the $10 mark. However, if you search for oil filled pressure gauge you’ll find most of them have a ¾” NPT connector, which of course will not fit on a hose bib.

That’s why I went with this gauge because it came with the coupling to make this connection.

Fluid filled water pressure gauge with 3/4″ NPT connector and hose bibb adapter

I will admit, I looked for this kind of connector myself for a few minutes without much luck before thinking–you know my time is valuable enough that I can just buy this for a couple dollars extra and get the video series going (linked below).

The good news is that you can still use it on whatever other project needs a ¾” NPT connector. But you will have to put this particular one together yourself. I recommend putting 3-4 layers of Teflon tape…

Teflon Tape Prevents Water Pressure Gauge Leak on Hose Bibb

Teflon tape prevents the water pressure gauge from leaking on hose bibb–you don’t need to create a leak when you are trying to find one. 😉

…before tightening it up with an adjustable wrench or two or whatever size wrench this is (I just happened to know where the adjustable wrenches were at the time). I really did use two, but I had a difficult time using two while trying to film…sooooo you only see one in the photo.

On the inside it has a nice o-ring to seal at the hose bibb.

Fluid Filled Water Pressure Gauge Gasket Prevents Leaks on Hose Bibb

The gasket inside the adapter.

In any case, this “YZM Stainless Steel 304 Single Scale Liquid Filled Pressure Gauge with Brass Internals, 2-1/2″ Dial Display, Bottom Mount,Oil Filled Pressure Gauge,Water Pressure Gauge. (Stainless Steel)” seemed like a decent answer and after having used it for *many* different leak tests. It performed beautifully for the camera with smooth drops (and spikes) in pressure over short and long time periods.

*Note #1: that ridiculously long named water pressure gauge is linked directly to the one I bought. There are others on that listing that I have no knowledge on, but definitely don’t get the black one because it is a dry water pressure gauge (unless, of course, you want a dry one, but definitely check around on reviews for those).

*Note #2: if you buy this water pressure gauge there is a sticker affixed to side with a couple notes and warnings:

Fluid filled water pressure gauge warning label.

DO NOT USE ON OXYGEN SERVICE
Warning: Severe personal injury or damage may be caused by pressure beyond to of scale, excessive vibration, or pressure pulsation, excessive instrument temperature, corrosion of the pressure containing parts or other misuse. Refer to ASME B40.100
After installation cut off the top or pierce the hole as shown.

With regard to the last point. There is a blue pressure releasing gasket on top. While the note recommends cutting off the tip, here in the desert where I can only imagine the hot and dry temperatures turning the silicone into a rock, I decided not to perform either operation.

The gauge read zero and after each test (or more along the lines of every week or so), I confirmed that it still read zero when there was no pressure. It maintained it’s calibration for the full 6 months I used it. However, if I needed to recalibrate, I still had the option to use a small flathead screwdriver or some other carefully applied means to allow a little air inside the gasket and put it back in place. YMMV.