Contractors Help!!! Need help disputing pier & biem issue.

[Michael Arredondo]

Hello biggerpockets community 

I need the opinions of contractors who are familiar with working on homes with pier & biem foundations. I want to know what is the required depth of a hole before a concrete cylinder is put into place? I have googled this and came across many different answers. I’ve come to the conclusion that 3ft is the average but would like other opinions. Any help and input is greatly appreciated! 🙏