This was an occasional but recurring topic on eBuild, including a topic that Jan and I initiated.  Our water supplier (Anglian Water) has a strict policy to the effect that: the pipe into the house must be a min of 75cm deep and their surveyor must review the house installation for compliance before scheduling any connection works on the public highway.  (There is a waiver for approved installers but in practice these guys only deal with large installations.) The standard way