A method of nonintrusive hydraulic fracturing monitoring based on high frequency pressure measurements has been known since 1985. Since that time, multiple attempts of its implementation into a commercial product have been tried. A new method using a wellhead pressure sensor during well stimulation was developed in 2017. The method discussed here is a continuation and improvement of this method. It is based on an advanced signal processing algorithm used for detection and analysis of tube waves in a wellbore and on the data science approaches for further processing of tube wave parameters and providing the answers of fluid entry point depth, plug failure probability, and casing leak detection. Use of the wellhead pressure sensor with a data acquisition box eliminates the need for sophisticated hardware. This enables cost-effective and timely decisions at the wellsite. The technique was validated in the field in several fracturing and refracturing jobs.