Water flow or pressure sensor

I have an irrigation system done with Sonnoff 4CH PRO R3 and is working very well but, time to time, I’m remaining without water from the main supply.
How can I have an sensor to send me an info/message in order to take an action ? What type of sensor should I use ?

floatless relay sensor or liquid level relay (hi/low). you can try those or simply set a timer so water source can replenish.

Un senzor de usa/fereastra DW2 WiFi modificat, mai exact daca se inlocuieste releul read cu un limitator actionat de un plutitor, asta in cazul in care sursa de apa este un rezervor. Sau inloc de senzorul de usa poate fi folosit un Mini unde pe S1 S2 se leaga limitatorul amintit mai inainte.