Monitoring Pool Water Level

I have an in-ground pool, and i want to monitor the water level so I can know when I need to put more water in. Anyone seen anything out there, that I can add to my existing pool without a crazy cost?

This interests me as well, though for a different purpose. I have a humidifier in a room with some equipment that is sensitive to humidity. It needs to remain at a certain level.

I’m getting a z-wave humidity sensor soon, but I’d also love to be able to monitor the water level in the humidifier so I know when I need to refill it. I thought about mounting a moister sensor at a specific level inside the humidifier but I don’t know if:

  1. it will dry out enough once the water level drops below the sensor. Obviously this will be in a very humid environment so I don’t know that it’ll ever really be dry.

  2. Are these things water proof? Is the water gets filled up in the humidifier it’ll probably submerge or at least mostly submerge the device. I know these things are obviously made to sit in water… couldn’t detect water otherwise right? But are they designed to be submerged in water?

The water level sensor can be fairly easily constructed using a piece of PVC pipe, styrofoam and a cylindrical reed switch like this one:

  1. Cut a piece of styrofoam that can slide freely into the pipe
  2. Attach magnet from the reed switch to the styrofoam.
  3. Attach the reed switch to one end of the pipe. Make sure the top end of the pipe is not sealed, so that air can move through it.
  4. Stick another end with styrofoam inside into the pool.
  5. Post pictures.

The ones I have seen are not submersible, but you should be able to hard wire the contacts on the sensor to two pieces of solid copper wire you could mount in the tank (keeping the sensor outside of it).

Inviting @wackware to this discussion since he is in the midst of a project like this.

Looks interesting, but I’m going to need something that is small and out of the way if I want a chance for my wife to let me use it. I would think there would be something out there, but no go yet.

you might be able to use a float switch for an evaporative cooler. They are submersible and used to control the water level in the pan.

Just had a thought… How about putting a multisensor in some kind of waterproof container and attaching it to your weir (whose angle changes based on water level).

It would take some time to calibrate, but once done it should be pretty accurate and certainly unobtrusive.


Was just searching for something along these lines and found this older thread. Not sure if this challenge was solved?

Just found this purpose designed device to monitor water level, I’m going to research some more but it appears it can interface with a secondary relay - that sounds straightforward to trigger something inside ST.


For a sensir you can use and then use the smartthing arduino adapter to interface.

Please be very very careful putting any electrical equipment, even a battery sensor, in the splash zone of a pool. (Two words: galvanic corrosion.) For example, the Aeotech water sensor can detect dry conditions, but is only manufacturer spec’d for freshwater, not chlorinated water. So you can use it with a fishpond, but not a swimming pool. (You’ll find discussions of swimming pool issues and why this is such a harsh environment in forum topics on pool temperature monitoring.)

Both Intermatic and zodiac/jandy make nice pool equipment which should meet code requirements in the US. Search the forums for discussions.

Basically this is an easily solvable problem with existing equipment which is both accurate and safe to use, but it’s not a cheap solution. Probably $400 for a unit which is certified safe for a swimming pool. So it just depends on how much you need it. For a rental property where you can’t count on the tenants to keep the pool filled, it might be a very good investment. :sunglasses:

Thanks. Will research that - I have the luxury of building in from new as this is for a new pool yet built.

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I rigged a water level sensor in my pond using this float sensor -®-Horizontal-Liquid-Switch-Sensor/dp/B00AKW29U2 wired to a GoControl window/door sensor that is enclosed in a water proof box.

I created an automatic fill, using a sprinkler zone valve wired to a transform which is plugged into a GE outdoor plug module.

Edit - Just wanted to note… I don’t rely on the switch to turn off the fill. I use Smart Light Timer, X minutes unless already on -

I also have it set to only run in Home mode, and also have it set to notify me when the automatic fill starts to make sure the pond doesn’t overfill :slight_smile:

If this is to keep the water level up in a new pool they can just put in a float connected to your water line. On my pool it is just a seperate opening from the skimmer so if water level drops it just turns on adding more until float goes back up.


OR, you could use a door zigbee/zwave sensor already compatible with ST instead of thereed switch