Staying in canada after US GC approval

Hi ,
Im a Canadian Citizen and was working in H1B visa .I got my GC approved recently .I use rent a house in US but i vacated recently as i work in border .Now living in Canada and commuting to work .
In the border the US customs and immigrations officers say i can take 1 year to move into USA.Though in the border customs and immigration officers told me , I dont see this time frame of 1 year mentioned anywhereofficially in any site or USCIS website.
Please advise

Thanks,
NF

Well, really if you continue to live in canada, yoru 'regular' GC is in jeopardy each time you enter. You should file an I-131 Re-entry permit if you intend to live outside US for more than a year (but this would have had to have been done wheile living in US). Your daily entries into US don't change the fact that you do not permanently live in US (which believe it or not is a condition of being a US Pemanent Resident, go figure) so you are at risk to being denied GC entry at some point.

The I-131 instructions:

http://www.uscis.gov/files/form/i-131instr.pdf

explain the 1 year requirement ... kinda.

What you should have is a commuter GC, which will not be contested by CBP when you enter, and allows you to live in canada. It is dependent on having a US employer however. The commuter GC is more like an H1 on steroids. If you lose your US job, you pretty much either forfeit the GC or must quickly move to US and convert to regular GC.

You simply can't have it both ways... for very long.