Q:

When do I give my two weeks notice?

I have received a written offer.  The new employer and I have both signed the written offer yesterday. The employer made a comment (before giving me the written offer) regarding how the start date may be in 2.5 weeks, but have not yet confirmed the exact start date.  I communicated to them then that I will be giving my two weeks notice to my former employer once I sign the written offer.
However, I have just completed the background check and have not yet taken the drug test (has not arrived yet)... so I don't exactly feel comfortable giving my two weeks notice just yet, even though I know I will pass (but just in case?).
Anyways, my question is 1) Is is appropriate to ask my new employer to confirm with me when I should give my two weeks notice, since they'll be the ones receiving my background check and drug test results (what's the best way to ask) and 2) When is it appropriate to give my two weeks notice (like what if I don't get my background check and drug test results within the next week, if I wait to have the results, I may not have enough time to give my two weeks notice to my former employer, which means I may not be able to start in 2.5 weeks...?)

A:

First, I am assuming that you are in the US.  Second, I am assuming that you have every reason to believe that your background check and your drug screen will be clean.
In this scenario, you need the new ("prospective") employer to give you MORE than two weeks notice of the actual start date, so that you can give your current employer the customary two weeks notice.  If they can't or won't do that, for whatever reason, you should consider it a BIG Red Flag.
The statement that your drug test "has not arrived yet" troubles me.  Drug tests are normally done in a walk-in or by-appointment controlled environment, either at the employer or at an independent lab.  This allows them to maintain proper chain of custody and ensure that you did not do something clever.  (Part of the standard protocol for a urine-based drug test is measuring the temperature of the sample.  This can't be done unless you are in their office.)  Yes, they have to send you paperwork, so the drug test facility knows who to bill, but this can be done by email, or by any of several overnight express services.

A:

This is difficult to answer in theory, but in practice fairly simple.
You ask your new employer to let you know a firm date as soon as they can, letting them know that you need to give notice (they already know that, so hopefully they have it covered and usually they do).
In the eventuality that you get taken by surprise, you just quit with as much notice as you can and walk out. The chances of legal action being taken against you are very very slim. So slim that I've never seen it happen. In theory you can be forced to do the two weeks in some places, but no one wants a disgruntled employee hanging around abrading morale for 2 weeks. I've walked out with 10 seconds notice more than once.
Do your best to make sure all your work is up to date and as clearly documented as possible to help whoever takes over from you. But you already have one foot out the door, focus on where your career is heading, not where it has been.
In most places security can march you out the door with zero notice, this is just marching yourself out.

