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Flume: Know About The Flow

As I’ve mentioned previously, household instrumentation is addictive. Further, it can draw out my compulsive tendencies. I’ve been wanting to add a smart water flow meter to our home for a while. This was motivated by the fact that we have gardens, and we occasionally forget the water is on. On such occasions the result is a soggy, boggy part of the yard and an unwelcome spike in the water bill.

A False Start

Last year, I tried an initial experiment using the Orbit B-Hyve Smart Hose Faucet timer. This device would only control one faucet, but under $60, it was cheap. I thought it a good experiment. The trouble is I could not get it to work for me. I was never able to get its little hub to connect to the device.

As a result, I returned it and began to investigate devices that would meter flow in the main water line from the city. I hoped that I could set an alert to tell me if we left the water running too long or into the evening. It would not turn off the water, just alert me that I had to do it.

Red Pill or Blue Pill?

I considered two kinds of add-on flow meters designed for DIY installation by the homeowner. One type, as embodied in the Stream Labs Smart Home Water Monitor, clamps onto the water supply line and read the flow using an ultrasonic beam sent through the pipe. They work with copper or plastic pipe. At our home the main water supply line from the city is plastic, so this could work for us.


However, I settled on the simpler approach used by the Flume water flow meter. It has a sensor device that clamps onto the city water meter. This senses the motion of a magnet on the rotating mechanism inside the city meter.

This information is relayed over a proprietary 950 MHz wireless link to a small bridge that connects onward to our Wi-Fi. The interpreted reading is available to a smart phone app and (of course) integrated in our Home Assistant installation.

Flume has a web page where you can check to determine that your existing water meter is compatible with their device.


Speaking of installation, ours was very simple. It was only slightly impacted by the actuality of our house. I started by putting the bridge in the central hallway where the core network switch is located. Given this arrangement the sensor and the bridge could not be paired.

It was immediately apparent that the brass mesh window screens across the front of the house caused a problem establishing the link between the two devices. This was remedied by relocating the bridge to a corner in the living room, about 5 yards closer to the water meter.

Once the bridge found the sensing device everything just worked. We started to accumulate historical data about our water usage. Even with the difficulty presented by our window screens, the entire installation took me about 90 minutes.

Flume App Screens

Flume App

The Flume mobile application (pictured above) is quite useful. Looking in settings it has two preset alerts:

  • Small leak alert – small flows lasting 2 hours or more.
  • High flow alert – flows of 5 GPM lasting 15 minutes or more.

Over time the Flume system evaluates flow patterns to work out what was tap, toilet, shower, laundry and other.

Home Assistant

Flume integration into Home Assistant was very simple. With the integration installed the device was auto-detected. A variety of sensors are exposed:

  • Flume Sensor Home Current
  • Flume Sensor Home 60 Minutes
  • Flume Sensor Home 24 Hours
  • Flume Sensor Home Current Week
  • Flume Sensor Home Current Day
  • Flume Sensor Home 30 Days
  • Flume Sensor Home Current Month

The only one I am really interested is Flume Sensor Home Current, the real-time indication of flow in-progress. This I have displayed on the main page of our HA UI.

Flume HA Flow

Clicking on it gets to a page where I can dive into history of water flow over a specific period of time, as shown below. Just looking at the pattern of flow as exposed in HA, some of this seems readily apparent. The notable thing is that, in all cases, the flow returns to zero after some rational amount of time.

Flume HA Annotated

Leak #1 – Trivial

A few weeks after Flume was installed I received an email alerting me to a potential leak. The alert indicated the start time and flow volume, which was very small, less than 0.1 GPH. I turned to the Flume app on my phone and it echo’d this info.

Hunting around the inside of the house I could not find any toilets running or faucet. I eventually found that a faucet in the garden was not entirely turned off. It was connected to a drip watering system, so the flow was not apparent. This faucet requires considerable torque to fully turn it off. Most likely Estella didn’t quite manage to turn it hard enough.

In this case, Flume not only alerted me to the leak, it basically told me that I should consider replacing these faucets with a shutoff that’s easier to use. This remains on my task list.

Leak #2 – More Serious

On Friday, July 29th, after reporting to my desk, I noticed a leak by way of the Home Assistant UI. Flume reported 0.1 GPH flowing from 8:20am onward. The flow was slight, so I ignored it for a time.

When I had the opportunity, I searched the house for likely causes. This time, all the taps, inside and out, were positively off. I turned off the shutoffs at the toilets. Still, the wee flow continued.

I turned off the shutoff to the garage apartment that is my office. Still, the flow persisted.

Flume July 29

Eventually, I discovered a trickle emanating from small crack in a galvanized pipe. It was at the outside rear of the house. Not in the garden, but servicing a hose that we use to water plants in pots. The old pipe was badly corroded. The trickle barely visible just above ground level.

Touching the pipe, the trickle turned into a small spray. This was definitely the problem. Being a galvanized pipe, I was not able to fix it myself. I shutoff the water at the meter and sought out the help of a plumber.


Had we not been alerted to the trickle, it would doubtless have become a vertical gusher at some point, when the pipe eventually broke off. That mostly likely would have been when one of the dogs bumped into it while rounding the corner of the house, chasing a squirrel or trying to get to the letter carrier. The flow monitor worked, triggering my OCD to go find the problem, no matter how slight.

Further, we’ve been reminded that we should be planning for a whole house re-pipe. Any remaining galvanized plumbing needs to be eliminated.

Stella has become accustomed to being able to ask me if there’s still any water on in the garden, rather than going to check it in person. I have yet to setup any of my own alerts for nefarious water flows.

In the future, Flume will be the flow sensing part of a larger strategy for automating the watering of the garden, under control of Home Assistant.

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