I smoke between 3 to 5 cigs a day. But the new job I want has a smoke free campus and I guess the do a urine test for nicotine?

How long is nicotine in UR urine after you smoke

I doubt they would go to the expense of running tests for this to enforce their policy.
Smoke Free Campus, simply means they do not allow smoking on site, not that they expect their employees to be non-smokers.

TBH, as you smoke so little, why not quit as part of your new position and challenge.