building services often refer to service spaces such as loading, garbage, M&E rooms, basically any staging or back-of-house type space.  Utilities are your power, water, gas, data, etc.

Natural light is neither of these. 

I typically hear these terms around the entitlement type processes; zoning, etc.

So, from entitlement, I look at utilities as sort of quasi-governmental agencies (monopolies).  These would be street, power, gas, sewer, storm sewer (or storm water works) water, where you can only get them from a single agency and are necessary for health, safety and welfare and normally have authoritative powers like review, easements, and eminent domain.

Services would be your teleco, cable, satellite, fiber, propane, wind or solar, and so on that you can source from whomever you want but are integrated with other things and regulated.  

Services might also include agencies like fire department access points, security lighting for police, garbage truck access, etc.

If you are looking at it from a architectural construction document side... I might go with it being a utility if the building owner doesn't own it; transformer, gas line from the street to the meter, ditto on water & sewer.  So once the gas/electrical line crosses the meter, it is the service and branches out from there.

Thanks Non Sequitur! 

mightyaa , 

That kind of makes sense to separate them in terms of "quasi gov" and " commercial" sectors. 

But then what's....lets say lighting & ventilation(comes under passive heating/cooling); Rain water harvesting etc would they be services too?

SB