I fight this every time it is reposted because it's not really that accurate and the information within can cause severe health complications. First off, THC is not water soluble, therefore water in ANY amount will not help other than to hydrate the body (which has negligible increases to basal metabolic rates). The poster also recommends using Furosemide, which is a loop diuretic which prevents the reabsorbtion of fluids by the kidneys. One complication that this medication has is that you are prone to losing high levels of potassium, causing an electrolyte imbalance and possible cardiovascular problems.

The tests that are run on a drug test include specific gravity, creatinine clearance, metabolite presence, temperature, color, and pH. A failure in one is a failure in all. By diluting heavily, specific gravity is altered, as well as urine color. By bulking with creatinine supplements, you can also alter specific gravity. Unless you've got a gas chromatographer sitting around your house, there's no way you can determine normal serum levels of any body product.

The problem with posts like this are that drug tests are extremely sensitive as well as incredibly subjective, varying heavily between person to person. If being drug tested for a job, the information included by the link is not terrible (although I'd avoid furosemide), but I would not rely on it for a court ordered drug testing sample. For that, I would suggest only smoking cessation.

If you're looking to decrease detection times, losing adipose tissue (fat) as well as exercising regularly and increasing your basal metabolic rate are the only true methods.