Just more knowledge for all. CSC basically is short for Certificate of Statutory Completion. Key word being Statutory.
This is, in layman's term, a collective acknowledgement / confirmation that approval is issued by all gov department (ie: in charges of water, sewer, structure, electrical wiring, fibre cable, etc).
So when you don't have CSC, your licensed electrician / licensed plumber can't submit to have incoming water, electricity, gas, telecom, etc.
How are you as a owner going to move in if property does not have incoming supplies.
I don't think any Singaporean would dare to mess with the tax man on property tax.
Simply put it. The building regulation links everything & everyone up to be responsible & liable. Even the property owner is liable. I strongly urge all property owner to read the fine print of all those documents you have to sign during the initial stage of the job (Both commencement of design / construction stage)