YOu should be safe after one – two weeks.
However hair hold drugs in it for up to 3-4 months

A general rule of thumb is… it take approx. 10 days for the THC from one joint to clear the body. Drink plenty of fluids, but don’t do it the day of the test. If your urine looks too pale and watered down, it’s a red flag that you’re trying to fool the test. Most of the ‘kits’ you’ll see for sale require you to drink LOTS of water the night before, and the morning of the test. The labs that perform the tests know all about them.

As A worker in a drug testing clinic and a avid pot smoker I would say if you only did it once and if your pretty active only a couple weeks. Water is your best friend right now water and sweating because thc stores itself in the lipids in your fat cells. good luck with that drug test thing….what else would be in a gooddamn hooka…jesus.

Hi marijuana takes 3 months to go out of your system heroin only takes 1 month you would think it would be the other way around considering heroin would be the stronger drug but marijuana stays in your system for 3 months i wouldnt recommend you ever smoke it again it might seam like fun but it will ruin your brain in the future its not worth it for the short amount of fun you might have,, to have a lifetime of your brain function slowing down and being paranoid also the risk of lung cancer and never feeling the same again once youve lost it you can never get it back , good luck with your job

Drug Testing And Other Possible Conditions Of Employment
_

While some may consider drug testing, credit checks, reference checks, and other pre-employment checks to be Gestapo tactics, they are a requirement for many companies. And, yes, in most cases they are legal. Remember that little section of legalese at the end of the employment application you didn’t really read? Your signature on that document is what gives them the right. So be ready to live up to the terms to which you have already agreed. By the way, if you look closely at your acceptance letter, you may notice that the offer is contingent on you passing whatever pre-employment checks and/or tests they may have. Even if it isn’t in the letter, it was probably contained within the application you signed earlier. Most employers consider these tests to be “conditions of employment,” and these conditions can be in effect even after you have started with the company.

An example of this “condition of employment” clause being invoked occurred when a recently hired grad was found to have lied about some information on the employment application. There have been numerous cases of graduates who have been hired and then fired by the new employer based solely on the conditions of that document. As long as you have been straight and honest, this should not be a problem for you.

On the other hand, the pre-employment check that many college students fear most is the pre-employment drug screening—and rightly so. A strong note of caution: if you have in the past or are presently using illegal drugs, you are strongly advised to stop using them—immediately! The day before—or even the week before—the test will likely be too late to achieve “clean” results. But if you make a commitment to steer clear far enough in advance, you may give your body enough time to detoxify and flush out. While many substances can clear in under a week, there are some that will stay with you much longer. I recently spoke with a graduate who had accepted employment, only to fail the drug test. Reason? He had used marijuana thirty-one days before the drug test—and failed.

There is no simple answer as to how long drugs will remain in your system, since the answer is influenced by the specific drug half-life, intensity of the usage, method of usage, length of usage, tolerance, fluid intake, body size, body fat, metabolism, andthe specific range which the drug testing lab uses to signify a “positive” for drug use. But the following table provides some general guidelines for the amount of time a drug can be detected by most standard drug tests:
Drug Detection Time
Alcohol 6–24 hours
Amphetamines 2–3 days
Barbituates 1 day to 3 weeks
Benzodiazepines 3–7 days
Cocaine 2–5 days
Codeine 3–5 days
Euphorics (MDMA, Ecstasy) 1–3 days
LSD 1-4 days
Marijuana (THC) 7–30 days
Methadone 3–5 days
Methaqualone 14 days
Opiates 1-4 days
Phencyclidine (PCP) 2–4 days
Steroids (anabolic) 14–30 days

Keep in mind that detection time listed above does not mean that the drug is fully expelled from your body within that amount of time—just that it has dissipated enough that it can no longer be accurately detected—or at least is not high enough to register a “positive” on a drug test. Most drugs are treated by the body as toxins which take time to eliminate. Rather than allow excess toxins to potentially affect vital organs, they are often stored in fat cells, making them typically difficult to release or detoxify from the body.

The basic drug test used by most corporate drug testing programs is called a “Five-Screen” (or “NIDA-5” or “SAMHSA-5”) which is testing for five types of drugs:

1. Cannabinoids (Marijuana, Hashish)
2. Cocaine (Cocaine, Crack, Benzoylecognine)
3. Opiates (Heroin, Opium, Codeine, Morphine)
4. Amphetamines (Amphetamines, Methamphetamines, Speed)
5. Phencyclidine (PCP, Angel Dust)

However, many drug testing firms now offer a “Ten-Screen” which expands to include five additional drugs:

1. Barbituates (Phenobarbital, Secobarbitol, Pentobarbital, Butalbital, Amobarbital)
2. Methaqualone (Qualuudes)
3. Benzodiazepines (Tranquilizers-Diazepam, Valium, Librium, Ativan, Xanax, Clonopin, Serax, Halcion, Rohypnol)
4. Methadone
5. Propoxyphene (Darvon compounds)

One major drug testing company is now offering the Ten-Screen for the same price as the Five-Screen. Result? Many employers end up testing for more, rather than less. Here is a list of other drugs that can be included in drug tests.

1. Ethanol (yes, that’s alcohol)
2. LSD
3. Hallucinogens (Psilocybin, Mescaline, MDMA, MDA, MDE)
4. Inhalents (Toluene, Xylene, Benzene)

If there is a drug out there, there is a drug test for it.

How about one more thing to worry about? Second-hand smoke from marijuana and crack cocaine can be absorbed into your hair. Problem? Some companies are now using hair testing to determine drug usage. Answer? Don’t even hang around others who are doing drugs. It can still be absorbed into your system and produce a positive test result. “I didn’t inhale . . .” is not a valid response. And sufficient second-hand smoke exposure can also cause failure of standard urine drug tests. You could fail both a primary and secondary test, with no recourse other than saying that it was someone else. It’s just not worth the risk.

So if you have been exposed to illegal drugs, your best insurance for a clean drug test is to stop using them immediately. And not just temporarily—permanently. Drug test or no drug test, using illegal drugs (and excesses of alcohol) will eventually catch up with you—sooner (if you are foolish enough to use them during work hours) or later (if you obliterate the rest of your life outside work).

Please note: this is not a lecture from Mom and Dad on the evils of drugs. This is a straightforward and honest warning from someone who has seen the negative effects that drugs can have in the workplace. Drugs have no place in work society today and never will.

If you are not a drug user and you fail the drug screening (it does happen), be as straightforward with the employer as possible, let them know that you are not a drug user and ask them if they would please do a confirmation test. Recent estimates from the Journal of Analytic Toxicology showed error rates of 5 to 14 percent on this initial test. The following is a list of over-the-counter medications which have been known to cause false positives in drug testing:

* Ibuprofen (Advil, Motrin)
* Midol
* Nuprin
* Sudafed
* Vicks Nasal Spray
* Neosynephren
* Ephedra and Ephedrine-based products (often used in diet products)
* Detromethorphan
* Vicks 44

There are more, but suffice to say that not every drug test is accurate. That’s why almost all drug testing companies ask you in advance what medications you are presently taking or have taken in the last thirty days. Make sure you list them all, even over-the-counter medications. Some drug testing companies will either have a doctor (or other medical professional) personally interview those who fail a drug test to determine if there was a potential false positive.

If you do receive a failing grade (actually referred to as a “positive” on your drug test—this is one test you do NOT want a positive—you want all negatives) on your drug test, ask to be retested with a confirmation or secondary test. Many employers do not automatically perform the confirmation test since it is significantly more expensive than the initial test. However, if they are unwilling to offer retesting due to the expense, offer to pay the expense on your own and then use a different testing service—ideally a secondary testing provider recommended by the employer so that you won’t have a credibility problem with the second test. If you are turned down in your request or you have additional problems, you may want to seek the advice of a competent attorney for further counsel on your available options

http://www.collegegrad.com/book/New-Job-Preparation/Drug-Testing-And-Other-Possible-Conditions-Of-Employment/