Introduction
Here’s a simple way to know when to refill your water softener.
I’ve seen multiple ways to achieve this, involving for instance an ultrasound distance sensor. However , the narrow space of the tank can cause issues and is not the best and easiest way.
This post is about a “very simple setup” : This setup doesn’t measure the exact salt level, but rather detects when it’s too low — specifically, when water becomes visible at the bottom of the tank.
Considerations about salt and corrosive environment
While this solution is simple and effective, it’s important to consider the long-term effects of placing electronic components—such as a water leak sensor—inside a water softener tank. These environments can be harsh due to a combination of moisture, salt, and mineral residues. Salt, in particular, is corrosive and can accelerate the degradation of exposed metal contacts and internal components.
Over time, the sensor’s detection pads may corrode or accumulate salt deposits, potentially leading to false readings or total sensor failure. This is especially true if the sensor frequently comes into contact with brine or is left sitting in a humid, salty environment for extended periods.
To extend the sensor’s lifespan:
- Minimize exposure: Only place the sensor at the bottom of the tank once the salt level is low and promptly remove it before refilling.
- Clean periodically: Wipe the contacts clean with a dry cloth or lightly dampened paper towel to remove any salt buildup.
- Protective measures: Consider coating the sensor’s circuit board with conformal coating (if accessible and safe to do so), or using a small non-conductive shield or enclosure that still allows water to reach the detection pads.
- Monitor for degradation: If you notice erratic behavior or false alerts over time, it may be a sign the sensor needs cleaning or replacement.
While leak sensors are generally designed to operate in damp environments, prolonged exposure to saltwater or salt mist may shorten their operational life. Plan for occasional replacements, especially if the sensor becomes less reliable.
Required Hardware
For this setup, assuming you already have HA and a Zigbee network, you only need one inexpensive device : A water leak sensor.
The device has 4 exposed pads, 2 on each side. When water touches 2 of these pads, it means there is a leak and trigger an on/off entity in Home Assistant by setting the sensor to Wet/Dry.
Note: my device is recognized by ZHA as a Sonoff SNZB-05, which it is not.
Home Assistant Configuration
So we have a boolean value to know when salt is too low : Sensor is wet.
To send the notification, I’ve defined an automation: If the sensor is wet for at least 5 minutes, notify me.
The 5 minutes delay is to prevent any repeating false notification. Please find below the YAML code of the automation.
alias: Adoucisseur - Remplir sel
description: ""
triggers:
- trigger: state
entity_id:
- binary_sensor.adoucisseur_niveau_sel
from: "off"
to: "on"
for:
hours: 0
minutes: 5
seconds: 0
conditions: []
actions:
- action: notify.notify
metadata: {}
data:
message: Remplir le réservoir à sel
title: Adoucisseur
data:
entity_id: notify.mobile_app_xxxxxx
mode: single
As expected, the automation sent me a notification this morning and I’ve added 50 kg of salt afterward. Just remember to remove the sensor before refilling the tank, and place it back at the top afterward.
Conclusion
Overall this is probably the easiest and quickest I’ve implemented in HA. This was also one of my first native HA automations as I usually used a Node-RED flow. It proved reliable and as such is my final setup.
