From what I am seeing, there are no public APIs, nor even an Alexa skill or anything for it. You are probably out of luck on connecting that app to anything, much less to Hubitat.
Leak Alerts: You can set up email or text alerts for continuous water flow to act as a real-time notification system
I believe there are community apps to scrape data from an email alert if you wanted to investigate that path, but it is nothing I have played around with.
