Topargee Water Tank Gauges


Monitor your water usage in your Caravan, RV or Marine Vessel accurately. Available in battery or 12v versions, flush-mount, surface mount and the new Bluetooth model. The good news is the sender is fitted in the hose line and there is nothing fitted to the tank.

Choose from:
Surface Mount Gauge $105
Flush Mount Gauge $140
Bluetooth Mount Gauge $155

Both kits come with an attached 1.4 lead

If you need extra leads, they can be purchased HERE!!
12volt adapter can be purchased HERE!!

Delivery: Next Day Despatch
$10 Flat Rate Australia Wide

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New Bluetooth Model & App Available

Our favorite Water Gauge just got better with the introduction of the Bluetooth model, allowing you to see at a glace just how much water is left in your tank.

Many campers will know how precious water is when out camping, especially when free camping or in some of the more remote areas of Australia.  Knowing how much water you have on board can be critical, and it also allows you to plan your trip better and know how long you can stay in one location.

Having an accurate water gauge can greatly assist with this.  Yes, you can wait till you are empty and use that as a guide, but that could also get you into trouble.

The Topargee Water Tank Gauge has two amazing features

1. It measures water flow accurately and will tell you to the litre, how much water you have left in your tanks.  The new Bluetooth model now connects to your smartphone via an App and has the ability to show the amount of litres remaining and express it as a percentage.

Available as Digital read out models or  new Bluetooth App Display

2. You don’t need to drill into or fit it to the tank.

Sender unit fitted after Water Pump – Not to tank

Most standard gauges work on approximate levels, full, med low, which does not give you a true indication of how much water you have on board.

Current water gauges only give a rough indication

The Topargee Water Tank Gauge fits into your existing pipe work and accurately measures the water flow.  It is that easy.

The added benefits is that you can start to work out your daily water consumption, and plan your trips better.  The original models (left image) show readings on an LED Display whilst the new Bluetooth Model (Right image) can be read via an App on your smartphone.

Measure your remaining water to the litre

You can measure how much water you are using per shower, or how much to do the dishes.

As the unit is not fitted to the tanks you can use it for any size capacity tanks that you have.

How it works

The unit is installed after the water pump and measures the flow once it goes through.  Once fitted you just enter in the total capacity of your tanks and the device will do the rest for you.  If you don’t know how much your tanks hold the device will go into negative territory and work it out for you.

See it working here

Fitting & Dimensions

LED Display Models

Because there is no drilling involved, the unit is easily retro fitted to just about any set up.  There are two models.

The Surface Mount model that has its own internal AA batteries which makes wiring very easy.  (Dimensions shown in diagram below.)


The Flush Mount model that is connected to the existing 12 volt system. (Dimensions shown in diagram below.)


NOTE:  Cut out approximately 55mm x 70mm (May vary depending on thickness of backing board)

NOTE:  It is recommended to place the units at eye level to read the display easier. (See diagram)

Bluetooth App Model

The New Bluetooth Model of the gauge works exactly the same as the other models, however, instead of a LED Display at the front of the receiver unit, the readings are all presented on your smartphone via the e Flow App.   The unit can be installed using 2 x AA Batteries, or a 12 volt adapter can be purchased separately so that you have the option to hard wire the unit your existing 12 volt system.

Once installed, it is simply a matter of downloading the eFlow App from either the Apple or Google Play stores.  The App will then scan for all available eFlow meters within range.  If you have more that one fitted, choose the one you want to read and the app will to to the main page and display the following

  • The Tank Name
  • Battery Status (If using AA Batteries)
  • Menu Setting
  • Litres Remaining
  • % Remaining
  • Nominated Tank Size

The App display from the Bluetooth Model

The Bluetooth Model still requires a header unit, however this unit does not have a digital display.  Please see diagram below for the differences.

The eFlow Header Unit (Left) – Surface LED Display Unit (Right)

Extra Leads

All units comes with a lead reach of 1.4m, but there is also a 1.4m or 3m extension lead available if required, and you can join as many of these together as you need to.

They video below shows how easy they are to fit.  We just fitted one to our motorhome.  We chose the surface mount model due to restricted wiring access.  The unit was easy to fit and we had it done in under an hour.

12 Volt Adapter

The new Bluetooth Model of the gauge now has provision to convert it from a battery powered unit which takes 2 x AA batteries into an hardwired unit that can be fitted to your existing 12 volt system.  The adapter may be purchased separately and the fittings allow for it be be easily fitted to the existing unit.

Unit Install

The video below shows how easy it is to install one of the units.

Video of installation and the unit working

What we think

A brilliant device.  Gone is the guess work.

The install was relatively easy.  I gauged this by the amount of times I swore, which in this case was only once as my head made contact with the chassis as my pump was located under the motorhome, but in most cases pumps will be within the motorhome and easier to access.  It was really a matter of just running cables, then clicking them in place.  There were a couple of screw-on fittings to the sender unit, and then the pipes just pushed into the existing John Guest fittings which are standard on most caravans or motorhomes.  The batteries came with the unit, so it powered up and worked accurately first time.

Being a large bus we are fortunate enough to carry a larger capacity of water than most.   But it is still critical for us to know how much water we have and how long we can stay in one location.  The Topargee gauge allowed us to do this.  After setting our gauge up, we were able to watch the water flow, and flow it did, as I watched 35 litres disappear in a 5 minute shower.  But, my wife assures me this was just for testing purposes.

The biggest advantage is that we have been able to work out how much we use per load when we do the dishes, or use the washing machine, so it really helps to manage our usage.  Now, instead of getting the red warning light, we know almost to the litre how much we are carrying.

The new model has the advantage of being able to see the display on demand and a lot clearer.  It has more information available than the LED display, including converting the tank capacity into a percentage.  Another advantage is that it maintains a list of records, which allows you to show a history of your water usage.  Each time you top up your tanks and refresh the screen a record of date, time and quantity remaining will be recorded.  From this you can estimate daily usage which is very helpful for planning trips and knowing how long you can stay in a location.  This can mean not carting along extra water if you don’t need to.


Problem Solving for the RV Water Tank Gauges

Screen turns on but amount does not change:

  1. Is the snake at the top of the screen moving when water flows? Normal condition.
  2. Is water flow in the direction of arrow? Refit sender in direction of flow.
  3. Teflon tape or something caught in impeller? This can be shavings from holes drilled in the tank at some stage. Remove carefully.
  4. Have the sender wires been cut and joined? No warranty!
  5. Try not using the extension lead, if fitted. (remove sender and plug into 1.4mt lead from display and blow into lightly to check)
  6. Press both buttons at the same time and release, H22 should be displayed. If “H22” is not displayed, keep pressing and releasing the Display button until “H22” is displayed. Wait until the screen turns off and the unit will memorise the setting. This is the correct code for the ½’ sender supplied with these models.
  7. Screen turns on and snake at top of screen moves but amount does not change. See Item No 6 above.
  8. Check if Ltr is displayed in the bottom right hand corner. See below to change.

Display is reading out by a large amount, e.g. 1 litre for every 3-5 litres, Etc.​

  1. If your display is out by a large amount it is usually because you have managed to change the sender codes (see item 6 above to reset) the other reason could be it is reading in gallons (see next section), .

To change from litres to gallons or gallons to litres:

  1. There is a small Ltr or Gal next to the amount displayed to show which mode you are in.
  2. Disconnect the power (or batteries)
  3. Press and hold the “PROG” button while reconnecting the power.
  4. Release the button after you hear the long beep. The display will be switched (from litres to gal, or gal to litres)
  5. Wait until the screen turns off and the unit will memorise the setting.

Screen stays on or locks up and will not respond to any buttons

  1. In the unlikely event that this happens, disconnect power, press the “DISPLAY” button to release any holdover charge in the capacitors, wait 30 seconds and reconnect power. Display will reboot and go through self check and restart.

Why isn’t my water use being recorded?

  1. Do not turn display power off until it has gone to sleep (10 Sec.) remaining quantity is only recorded in memory after the display has gone to sleep.​

Why can’t I fit the sender before the pump?

  1. If you have no room after the pump, the sender can be fitted before the pump. The main reason we stopped recommending it is if you do not tighten all connectors properly and there is a tiny pin hole, air will enter the hose line and the water will drain back into the tank. If the sender is fitted on the pressure side any leaks become obvious. So basically it can be fitted either side of the pump if everything is fitted correctly.

No Display:

  1. AA battery models: Batteries fitted wrong way. Remove and replace correctly.
  2. 12v Models: Connected in reverse. Connect red wire to positive and black to negative.

Screen flashes on when no water is being used:

  1. This can sometimes happen if the magnet in the sender stops next to the Hall Effect sensor inside the sender unit and there is any slight movement in the RV. Simple solution is to open and close a tap quickly to move the impeller to a different position.
  2. Another choice is to turn the pump off if the 12v power for the display is coming from the same circuit (this is the recommended power source for the H2F-FM 12v model).
  3. Another cause of this problem is if the water pipe does not have any water in it and the impeller is free to turn in air. This can sometimes happen if the sender is fitted to the inlet side (suction side) of the pump. In this case turn the display power off. All settings and quantity will be memorised.
  4. If the sender is fitted to the suction side of pump and there is a slight drop in pressure caused by an old pump (unable to hold prime), air getting into line or severe corrugations could all cause the unit to flash on. This is another reason we recommend the sender be fitted to the pressure side of pump.

Screen turns red: (H2F-FM only)

  1. This will happen if the battery voltage drops below 9 volt.
  2. When quantity reaches 000 or -001 the display will turn red and buzzer will sound.

Download the free eFlow Apps

Version 8 or later

Version 10 or later

* Download the free eFlow App from Apple Store or Google Play.

​* Click the eFlow icon to start the App. The App will scan all available eFlow meters within communication range. Choose the one you want to read.
Allow device location, turn on Bluetooth, enter password.
​The App will go to the main page and display the quantity remaining, programmed capacity, % of tank remaining and battery status.
On the right hand top corner is the icon to refresh the information and the menu list icon is on the top left corner.

* Click the menu list icon (hamburger) on the top left corner of the main page.
Device name setting:
Rename your device.

Water volume setting:
Enter the usable capacity of your water tank/s.
You may need to run a tank through to check the usable capacity of your tank.

List of records:
This will show a history of water usage.
Each time you refresh the screen a record of quantity remaining will be recorded here.

Whenever you refill your tank press reset to reset the quantity to the pre-programmed amount.

Password Change:
Password is 0000. You can enter your own password.
We suggest you do this to save any problems with other vans close by.

Scan List:
If you have more than one meter, all available eFlow meters within communication range are displayed here.

Exit from the App.

Installing the sender:
Fit the sender in the water hose line as shown below.

The Bluetooth unit comes pre-wired with an approximately 1.4 Mt sender lead.  Sender leads cannot be cut and
joined, doing so will void warranty. Extension leads are available for the three pin plugs.  Extension leads should
​only be required if you are having communication problems e.g. inside a metal box.
The thread specifications of the sender unit are 1/2″ BSP male.   Make sure the sender is fitted with the water
flow in the direction of the arrow.  For best results sender should be fitted to a straight section 200 mm from pump & any 90 Deg.
elbows.  You will need to purchase two 1/2″ BSP female connectors to the size hose you have, usually 1/2″ or 3/4″
and two clamps. “John Guest quick connectors” have fittings to suit their hose and the 1/2″ BSP sender unit.
The H2F-BT12 can be fitted in any convenient location, inside a cupboard, etc. there is no need to have it visible.

Open the battery compartment and install two AA batteries.  The buzzer will sound and the Blue light turns
on for three seconds.

Connection to 12 Volt DC:
If you have purchased the 12v PCB adapter remove the battery holder and the screw from the battery compartment, then plug the adapter into the two pin plug coming from the battery compartment.  Connect the black wire to the negative terminal and the red wire to a fused (0.5 or 1 Amp) positive power source.  All settings and amounts will be memorised if power is disconnected.

Can not find eFlow Meters or Stuck
> Go to Setting > Google > Location
> Choose OFF

Quit from Setting
Quit from eFlow and enter it again.

eFlow will ask you location permission,
choose YES.

eFlow shuts down
> Go to Setting > Apps > eFlow > Storage

Quit from Setting
Quit from eFlow and enter it again.

22 reviews for Topargee Water Tank Gauges

  1. Robin Dick

    This was the second Flush Mount Gauge I’ve bought from these guys and I use these on my liveaboard boat at Hope Island.
    The service is great even to the extent I forgot to buy the extra lead to reach the water unit and the local guys delivered it to me free of charge.
    I know they advertise this for vans & motorhomes but they work great in boats and this lets us know our water usage as well as our tank status which is important if out on anchor.
    Also tells us how much we use for say a shower or washing machine.
    Alarms us when tank is near empty. easy to set and use. Big plus is it tells you if you have a fresh water leak by Flashing light on unit
    Have now given details to several of our dock mates, so expect a few extra orders.
    Robin & Rosalind

  2. Kimberley

    I got the topargee water gauge for my birthday from some friends and I did not think I would want one Now I absolutely love it. It was easy to install and the accuracy level is fantastic
    I highly recommend this as I now don’t have to worry when I go out on my big trips in the van

  3. Darla

    My partner and I were given the topargee water gauge as a gift as we do a lot of travelling in our caravan. Truly we don’t know how we ever travelled without this unit. Now I can monitor how long I can shower for or when to cut it short
    Without my partner worrying

  4. Stuart

    What an awesome product . No more guessing , more importantly , no more unnecessary holes in your water tank for those senders that have in my case , fallen out and subsequently emptied it . Great for those odd shaped tanks that are near impossible to get an accurate reading .The install is so easy, in my opinion you cannot go past the Bluetooth version.

  5. Guswhite

    Now I know how much water I have used and what’s left in the tanks. The Topargee arrived very quickly after ordering and was a breeze to install. Just had to add some extra pipe and fittings to install as per the instructions.. I have found the gauge to be very accurate which gives me confidence in managing my water usage. Highly recommend this product

  6. David Jeffrey Rose

    The Flush Mount was easy to install (other than needing to a contortionist to put it where i wanted it) and i wired it directly to the water pump which is great as it only turns on when you use the pump. Easy to program and read display.

  7. Ben O

    What a brilliant product it is a dream come true awesome thanks so much

  8. Lisa Bailey

    Quick postage , well packed in a cardboard box for safe delivery. After a trip to bunnings for hose fittings , it took less than 15 minutes to install our flush mount system . Looking forward to being able to easily track our water usage . With 3 kids on the road this is a crucial item for your water tank system.

  9. Joseph Misiaszek

    No more guessing , easy to install recomend for every van or any water storage tank to show water usage

  10. Mike Berry

    Excellent product that was so easy to install. Took me about 10 minutes and after running several litres of water through the tap it appears to be very accurate as well.
    Absolutely would recommend the product and the quick service was terrific.

  11. Campbell Michell

    I purchased the flush mounted kit so as to utilize the 12 volts that is readily available from the pump or the existing water tank gauges I just had to purchase some additional John Guest fittings and hose/pipe to ensure it was 200mm from the outlet of the pump, as per the installation instructions. Fitting both the sender unit and gauge was very easy and calibrating the gauge to the 480ltr water capacity that the caravan holds was a breeze. I mounted it next to the existing tank gauges so as to use in combination as stated in an earlier review the Topargee will not show a leak if it is prior to the sender unit. I would highly recommend the purchase.

  12. Bob Arnold

    Delivery was great instructions easy to follow for such a small unit it works extremely well should have fitted one a long time ago fantastic ???

  13. Steve Sparrow

    Extremely fast delivery
    Easy fit up and operates as described
    Finally will be able to have an accurate level displayed
    My wife is very pleased with the new gauge
    Have recommended to my friends

  14. Tony Johnstone

    A great concept and very convenient for keeping tabs on your water usage and quantity remaining. Very easy to install – a home handyman can fit it no problem. My only criticism is that the two wires on the back of the display unit are 10 mm clear of the front facia plate and point downwards, meaning that it is tricky to fit it to the standard 12 mm walls on caravans. Also, the wires straddle the lower screw hole making it quite a challenge to physically use a screw in that location. Otherwise, it is a breeze.


    I have just rated the Topargee as “Good” because “so far so good” with timely arrival of a product that actually delivers on its claim of easy to install. I anticipate that after our next trip the rating will be “Perfect” as we look forward to water usage via a gauge that takes the worry out of water control. I have looked and looked and you won’t find a cheaper or more convenient offer than purchasing via the Free Camping Shop. If you are reading this you obviously need one. Happy shopping and happy caravanning …cheers Glenn (just another traveller)

  16. Matt Krumins

    Works a treat and is very easy to install 🙂 Thanks guys

  17. Jocey Pocock

    Wow what a fantastic product! It is awesome to have a more accurate idea of how much water you have used, especially when you’re off grid exploring, to know how much you have left:) It is so easy to install and operate, and is one of the most practical and important bits of kit you can invest in. Highly recommend the purchase.

  18. John

    Installed 2 on wate4 tanks in my truck. Easy to install and super easy to use. Great to be able to see water usage and what is left. Have intentions now of installing on the van as well. Perfect world is to have a gauge showing full, half or empty in combination with one of these gauges. The only negative to the Topargee is if you have a leak it will not show. Hence with using the old style of gauge showing full, half or empty would have the perfect set up for remote travel . Topargee…… great product, easy to set up and easy to use.

  19. Geoffrey Nash

    installed in 20 mins works great. awesome product thanks guy’s

  20. Graham Meneilly

    No more guessing, know exactly how much water left in tanks, easy to fit, highly recommend.

  21. Bill McMillan

    The flush mounted unit is easy to read and the installation was a breeze after looking at the demo supplied on the site !…. plus I got a discount after registering as a Premium Member …….whats not to like about that !

  22. Elaine Curnow

    Thank you for the Topargee Water Tank Gauge we have installed it and have tried it out we are very pleased and happy that we bought this device and will tell other people on our travelles,once again many thanks.

    Regards Eaine

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