Hi,
PH has nothing to do with water softness.
PH only measures how acidic or basic a solution is.
If you want to test the softness of water with a digital device, use a freshly calibrated digital EC/TDS (ppm) meter.
The unit of Water Hardness measurement is usually ppm (milligrams per liter).
In JADAM the water is considered soft water if it tests less than 20 ppm.
Pure rainwater has a hardness of about 5 ppm.

You can also do a simple test with JWA.
Grab a clean bottle and fill half of it with the water that you want to test.
Put a few drops of JWA in the water.
The water will remain clear if it is soft water. It will also produce lots of foam when shaken.
If the water is not soft, it will become murky like milk and produce only a small amount of foam when shaken.
Be aware, that in order to perform the JWA test correctly, you need JWA that has a clear color. If yor JWA has a milky color, it will always make water look milky, even if the water that you want to test is soft water.