The main problem is that there is no such thing as 'a COTS solution for a water billing system with little custom code'. The only thing that exists is what com

The main problem is that there is no such thing as 'a COTS solution for a water billing system with little custom code'. The only thing that exists is what companies like Oracle and SAP market as such, claiming their solution only requires 'configuration'. They confuse their customers with misuse of terminology, because in fact that 'configuration' consists of a lot of custom code that is needed to adapt their solution to a specific purpose. Whether it is more or less code than honestly and transparently assembling such a system from available OSS components is besides the point as long as customers are not crystal clear on the fact that COTS solutions rarely exist, except as components for a purpose-built system. A claim of having a COTS solution is almost always a sham for any reasonably sized project.