Hi Nichiyobi,
I did not on apply immediately for the utilities when i collected my keys.
I received the Application Form from SPServices and i filled up the form and just faxed to them.
You can choose to turn on the Electricity & Water first which needed it for renovation. Gas supply can be turn on in later part.
You can log into:
http://services.spservices.sg
Click on the Application Forms & download this Utilities Application Form (For the supply of water, electrical and/or gas) or you may apply it online.
You may give them a call at 1800-2222333 to confirm their fax number and fax to them.
They will takes 3 working days to turn on the supply. You may also state your preferred date of the turn-on as well. But do note that you must be present at your house when the technician come to your house to turn-on.
Hope the above can give a good information for you.