Leak sensor saved the day

Yesterday a leak sensor in the secondary drain pan under the AC unit cooling coil in the attic saved the day. I was out of the house with my wife when I received a notification from HSM that the leak sensor detected water. During our drive home I impressed upon her the damage that we would have if the secondary drain pan overflowed. Upon return I found some water in the secondary drain pan but it was not high enough to run out the overflow drain or trip the float switch hard-wired to the AC unit.

I was able to get an AC tech out who unclogged the drain line. Problem solved.

Yes, the float switch probably would have shut off the AC, but with 100 deg days here in South Texas, that would have been an inconvenience, to say the least.

The best part was my wife admitted that Hubitat saved the day! :grinning:


I've had many HE saves

  • Kids filling water balloons in the bathroom and getting water everywhere, literally
  • Washing machine had too much soap and it came out the back vent and ran down to the floor
  • Dishwasher decided to spring a leak
  • Hot water heater recirc pump had a small leak
  • Sink hot line wasn't tight, found it right after we bought the house and moved in
  • Bottle of cleaner knocked over under the kitchen sink and the lid wasn't tight
  • Wife decided to clean the water sensor



Oh, the joys of home ownership. :grinning:


I had one just two weeks ago myself... Kid broke the back of the toilet (don't ask) - shattered it. Leak sensor by the toilet triggered, my automatic water shutoff valve to the house closed.

I'm not sure my kid would have known how to shut off the water himself (even though he's been shown multiple times... kids).

So I imagine water would have been spraying everywhere until I was able to get home from work to address it. Probably would have been SIGNIFICANTLY more mess and maybe damage.


This is amazing! I'm currently waiting for different water sensors from AliExpress & Amazon to test. Do you all have any suggestions on where to install them? This is what I have so far:

  • Behind toilets
  • Under sinks
  • Around propane hot water heater
  • Around well water pressure tank
  • Under dishwasher
  • Under washing machine

Here are other things I'm not sure needs one or not:

  • Clawfoot tub?
  • Chest freezer? Stand up freezer? Refrigerator?
  • Ice maker?
  • Hydronic radiant flooring. If this leaks, where is water likely to manifest? I don't know much about them at all.

Open to anything else I haven't thought of.

Some thoughts....

The leak sensor may not fit under the dishwasher. I located mine on the floor beside the dishwasher. Any hose leak should wet the floor enough to trigger the sensor. The flexible hoses to the dishwasher are the likely suspects to leak.

Do you have a free standing ice maker or built in to your freezer? If built in, a sensor on the floor next the freezer should work.

Not that familiar either with hydronic radiant flooring, other than understand that it does provide comfortable heat. If the piping breaks in the slab I am not sure that a leak sensor would help. Is the system connected to a hot water boiler? If so a leak sensor on the floor next to the boiler and pipes might be a good idea.

Other than that your other items are likely candidates for a leak sensor.

Thanks! I was planning on using just a wire like this attached to a leak sensor. I believe the entire wire is a sensor and I would think that would fit but I'd have to look.

Our ice make is free standing and I was planning on doing the same setup. Yeah I just asked our contractor about how leaks manifest for the hydronic radiant flooring and he says it would leak in the slab. There is apparently some pressure relief hardware in the system that may give "false" readings. I'll have to figure that one at later. And yes, the hot water is connected to a boiler.

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If you want to know what can happen without leak sensors, have I got a story for you. :face_with_spiral_eyes:
My brother in law hates winter and went to florida for months a few years back. This was after having his laundry room renovated. The contractor moved the water lines to the outside wall and didn't properly protect or warm the pipes to protect from freezing. so after about 3 weeks in Florida, my BIL gets a call from his neighbor and says, "hey bro, you got water flowing out your back door". We don't know when the pipes ruptured, but the amount of water was incredible. Enough to ruin the entire 1st floor hardwood planks (Brazilian Teak), turned the basement into a 2 foot deep kiddie pool, destroyed the kitchen cabinets. Enough water that the entire plywood subfloor had to be ripped out with the teak. He also had probably 15k worth of furniture and goods stored in the basement. Killed the furnance. It was close to 100,000.00 worth of damage. Not only that he had to live in a hotel for months as walls, floors, cabinets, appliances & beams were replaced.
He now turns the water off when he goes away.


Another layer of security to consider is a system like Flume, Flo, or Phyn to help protect against leaks in places with no active monitoring.

Flume may not be compatible with your water meter, but if it is, @tomw has an awesome Hubitat intergration for it. It would require a separate smart shutoff on your main line though.

Flo and Phyn are similar in that they monitor usage for unusual activity and can both shutoff water on their own.

Not sure about Flo, but Phyn unfortunately has zero non-cloud integrations.

I use both Flume and Phyn (in addtion to numerous leak sensors and a couple Titans!)... I set the Flume up a long time ago, and then added the Phyn when my plumber was doing a bunch of other remodel work for us, and gave it to us at cost with free install.

Now that I've had both Flume and Phyn running for a while, they are both impressively good at detecting unusual activity and calling it out. I do really like that Phyn regularly tests my entire system for any leaks - that's a nice warm fuzzy. Overall, I trust Phyn's monitoring & logic more than Flumes's though.

I like Phyn over Flo for one big reason -- Flo uses a mechanical impeller to monitor flow, and they've had pretty serious issues with those things coming apart after install. Phyn uses ultrasonic flow sensing (and it's excellent), so nothing mechanical in the pipe.

Many folks like Flo simply because it's a Moen product, but Phyn was engineered by Uponor -- they aren't as well known at the consumer-level, but (IMHO) Uponor has way deeper and more impressive plumbing chops than Moen.


Sorry this happened.....even to your brother-in-law :grinning:


Ha, That's my favorite!


rushes out to throw random water leak sensors everywhere

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May not be an option but my house is on a crawlspace and I have placed sensors under each bathroom with a large catch pan. This recently caught a leak in the drain of a bathroom shower. The drains for both bathrooms had probably been leaking for some time when I bought the house. Originally the house just had sand under it. So seeing a leak from a drain line was almost impossible, The sand would absorb the water and it would appear dry when under the house. I have since put in a vapor barrier and dehumidifier, due to having very high humidity under the house. I thought I had a leak as I was finding water pooling on a outside wall, turned out it was the humidity under the house and an air leak to the outside. After a few days of the vapor barrier installed I found water under the house pooling on the barrier. The drains from both bathrooms were leaking. I got those fixed and added the pans and leak sensors. That was back in 2021.

One of the drains I had fixed started leaking again a month or so ago and the leak sensor caught it within a few minutes.


Thank you! I'll definitely check these out. I'm racking my brain on what to do about the hydronic radiant floor heating. I haven't really looked into it, but maybe these are the answers I'm looking for.

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That's awesome! Great tip on the catch pan + sensors. We definitely need to do something like this in our laundry room directly underneath the main bath shower & tub.

I am pretty much a hype man for leak sensors. Multiple small savings, but one big one. My water heater burst a seam at 10pm one evening. My Sonos and Alexa devices hollered, so I tore downstairs to find a scene reminiscent of summer time play by the fire hydrant. I shut off the water valves and used more towels than a person should own. Without this warning, I would not have have known until my shower 10 hours later. All that time, the incoming water line would have kept pushing water into the tank, dumping onto the floor at full force. It would have destroyed the floor, furniture, etc. in my finished basement.

I agree with the placements previously discussed. I also put them around HVAC condensate pumps. Mine line outside would freeze, which caused those pumps to overflow. And, if your kids are helping themselves to your kegerator when you're gone, put on under the removable drip grate.


Just read this thread and am currently using the Flume sensor.
Works ok for me and mounting on my water meter was easy and it detects flow just fine
it is NOT local (uses wifi) and has delay when reporting.
Because it is cloud based (I don't like cloud for anything!), it is relying on their servers to report so that IF my internet goes down, I don't get the reporting, and it can take MINUTES before reporting a leak.
I looked at the Phyn and they have two different leak sensor, the Phyn and the Phyn gen 2.
All that I can see that is different between the two is the gen 2 has a shutoff valve in it.

is the phyn local?
What are the advantages between the two of the different generations?

Any Phyn owners here and which one do you have?
Is it local control/reporting?
Does the gen1 use pressure drop to determine a leak vs. normal useage?

Phyn is not local, but without an internet connection, the Phyn2 still has the capability to shutoff water if it detects what it thinks is a leak. That's an optional feature you can enable once its learning process is over, and is seperate from its (also optional) auto-shutoff capability when it's online.

I don't know anything about the original Phyn - I never had one.

Thanks for the info!
I am going to integrate the Flume with my water shutoff valve ( a Zooz Titan valve operator), but the problem remains with the Flume.... IF I have a leak and the internet is down (not a regular occurrence but it could happen), my HE rule would not receive the leak detect and not shut the valve.
This is different with the Phyn as it can shut the valve without internet like you said.

Yeah, there are a lot of scenarios to consider... Am I away, and power out but internet up? What about power on but internet out? Both out?

But in reality, how likely are each of those scenarios? And that answer will be different for each of us, depending on quality of local utilities, internet setup etc.

So my view is to solve for what's most likely and take your chances on the rest... If I'm away, power & internet are both out, and I somehow find out I have a leak, then there's a pretty good chance that may be the least of my worries.

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