Water/Shower Flow Meter

With all this lockdown going on, I’ve been over thinking. My latest thought being, how can I make my shower a little more connected. I have Hue lights in the Ensuite along with a ZWave motion/temperature sensor. Presently I have a rule in place that waits 60 seconds after the motion sensor reports as idle before switching off the lights, I’m forever leaving them switched on. This works to a degree, but as you’d expect has it’s flaws. So knowing if water is flowing through the shower would massively improve the WAF and overall experience.

Is there such a device that you can attach to a shower water feed to report on the flow, not after anything fancy though. Just whether or not water is flowing


I’ve got a strap on thermo-switch that works quite well.
Which I use as a trigger in openHAB2 to switch some funky lights on / off and cast / stop a radio station to the ChromeCast Audio in the room.

Like this


I’m also thinking of strapping some One-Wire temperature devices to the output (s) of my 3 way shower mixer tap, so I can tell if the bath is being filled or what the shower flow temperature is.

I’ve also got 2 x 60Lt per minute flow monitors in the main water supply, which tells me what the incoming cold flow and how much of that is going into the boiler for hot water.
So with a bit of maths, I know

  • Total amount of water entering the property
  • Of which is used as Cold
  • Of which is used as Hot

You can get strap on Doppler sensors, but they aren’t cheap by any stretch of the imagination

Is this the kind of thing you’re thinking of?


@MDAR nice idea, :+1: I have a few extra sensors not being used so I may do this with my home automation setup.


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Just an idea… since you plan to work with pipes… isn’t it better to get a normal water meter? Some of them report volume flow, next to volume. Standard european equipment (OMS/WM-Bus) can report state every 40 seconds or so. Eventually you can give a try to BLE sensors who catch diode blinking. I think I saw something like that before.


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Thanks for the replied everyone.


Can you tell me more, although I enjoy all these different technologies I’m by no means able to build stuff myself. I would be interesting in understanding how you’ve achieved your solution.



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There’s a number of ideas / solutions there…
Which one are you interested in?

I’m happy to explain one at a time, incase you decide that the idea you thought you’d like turns out to not suit you.



Hey gang

I know absolutely NOTHING about Z-Wave and don’t have any use for it.

So can anyone help @Maximo by saying if something like this would be of use?


If I’m reading it correctly, it’s part of a kit that means he could measure the temperature of a number of pipes / tanks with his Z-Wave setup.

Hi Stuart,

Thanks for replying, I was hoping you’d be able to explain what you’ve setup here.




For a second I thought you’d be asking about the difficult bit.

I’ll spend some time creating a proper reply tomorrow.

I use NodeRed for the logic, but if you prefer DSL or NGRE, I’m sure once you’ve seen how I’ve approached it, you’ll be able to recreate it.


So, I thought the best thing to do might be to clean up the flow tab that I use for this bathroom magic and share it.

The triggering part is quite straightforward.

I have a strap of temperature sensing switch (I think it is of the >30°C variety) that closes a contact when the pipe exceeds 30°C and opens the contact when it gets below ~25°C.

This presents to a Channel in openHAB2 as “Pressed” or “Released”

There are also two other buttons that I use to manually trigger the lights and music. (until such time as I fit some sensors to the other pipes (bath filler and hand held shower head).

These are in the “Triggers” section of the flow.

All the Comment Nodes have more details inside, if you are looking for extra information.

If you’d like me to export just a small section of the flow, just let me know.

Good luck.

(I hope you get plenty of WAF)

The Nodes in use on this flow are :—





I tried posting the text of the flow, but apparently that was >20,000 characters more than permitted, so it’s in a JSON file that can be downloaded here

Thanks Stuart, that’s very useful.

I made some research some time ago as well and found following BLE connected shower flow meter.



That’s just the thing I’ve been looking for. Thanks for sharing the link. I’ll get one ordered and see how I get can it integrated into my solution.

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Nice catch :slight_smile:

Can you explain how you’ve got it linked to openHAB2? (Obviously via Bluetooth, but is it a difficult thing to setup?)

It’s a little more than the cost of some One-Wire sensors, but a lot easier to install.

Well, I don’t own that (yet), but basically it need bluetooth binding extension to openHAB, which is rather easy to implement. I just implemented support for Airthings radon / air quality BLE sensor and PR was around 900 lines where the code itself probably half. Before someone implement the binding, it should be rather easy to read via python script if you have any programming background. Of course you need BLE dongle as well and most probably rather close to the shower.

I actually asked some details about it (BLE specs etc). As it takes power from the flow (no battery), it can be read basically only when there is a flow. Not sure if there is any backup power like supercap which let then read values e.g. couple of minutes after last shower.

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