How Much Water Dilutes Your Urine?

How Much Water Dilutes Your Urine?


Doubtlessly, water can dilute your urine, and dilution is the most common technique to evade the drug test. The exact amount of water that can dilute the urine is hard to say since it varies from person to person.

Some studies state that drinking about 8 to 10 glasses of water within 2 hours can dilute the urine. Others put forward that drinking between 27 and 34 ounces of water per hour maximum may not affect a healthy human body's electrolyte balance ratios.

The bladder of an average healthy adult can hold about 2 cups (16 ounces) of liquid. The period for ingestion varies to how much water you consume. It may take about 45 to 120 minutes for the ingested water to begin pushing the urine out of the body.

Dilution of urine can be intentional or unintentional. Some people drink lots of water to evade drug tests, but some people do it to maintain hydration or at the advice of a physician. Drinking plenty of water may lower the drug concentration in the urine due to frequent urination. It may send warning signals during urinalysis and raise suspicion leading to a failed test.

Table of Contents

What is a Diluted Drug Test Sample?

A diluted sample signifies a reduction in strength, concentration, purity, or quality compared to a normal sample. A diluted urine specimen would have drug or drug metabolite concentrations less than the normal urine with an imbalance of certain elements. Such samples may not produce accurate results and may be deemed unfit for testing.

Furthermore, the specimen’s color, texture, and pH get altered due to frequent urination making its concentration weak enough to get disqualified for testing. During testing, a diluted drug testing sample may produce an incorrect result. There may be various causes for urine dilution, including on purpose.

Causes of Urine Dilution

An employer may subjugate any employee to a urine drug test to check for illicit drug use. An employee who consumes drugs may attempt to tamper with the urine to pass the drug test. Therefore, diluting the urine would be the most commonly chosen method for many, leading to a diluted drug test result.

Urine dilution can be done accidentally or intentionally to dodge a drug test. Some of the various reasons include:

  • Hydration:  Many people rely on the significance of drinking enormous water, knowing its health benefits. Hence, they frequently drink plenty of water to keep themselves hydrated. If this practice is followed as a routine, there are high probabilities for their urine to be diluted.
  • Preparation before Drug Test:  To provide an adequate urine sample, many people tend to drink lots of water before the test to avoid returning for a repeat test. Hence, this leads to urine dilution at times.
  • Prevent Drug Trace Detection:  Most drug abusers attempt the dilution method to dodge the drug test. The dilution method may work for infrequent drug users in lowering the concentration levels of the drug, but scarcely for regular and heavy users.
  • Kidney Disorders:  Kidneys help in filtering the wastes from the blood and excrete them through urine. If there is improper kidney functioning, they will release more water into the urine, thus diluting it.
  • Diuretics:  Some people are prescribed diuretic medications for certain medical conditions. These diuretics increase the production of urine, leading to dilution. People who drink lots of tea and coffee may also have diluted urine.

How Laboratories Detect Diluted Specimens?

Visually, a tester generally checks for the color of the urine specimen. The color of the diluted urine will be lighter than the normal urine. The validity of the specimen is done to determine if it is diluted or not. The tester also checks the creatinine and specific gravity of the urine specimen.

  • Urine Creatinine:  It is a compound produced during the metabolic process of creatine, found in the blood and eliminated through urine by the kidneys. The normal creatinine range between 20 and 400 mg/dL in the urine. The diluted urine will have a level between 2 and 20 mg/dL.
  • Specific Gravity:  Specific gravity signifies the density of a substance in proportion to the density of water, thus indicating the concentration. The specific gravity for normal urine is between 1.002 and 1.030. If the specific gravity ranges between 1.001 and 1.003, the specimen is marked diluted.

How Do Drug Screening Tests Work?

Urine drug screenings are done by two methods - Immunoassay and Gas Chromatography-Mass Spectrometry.

  • Immunoassay:  Immunoassay is generally used for preliminary testing. This test is quick and inexpensive. In this type of drug test, antibodies are used to determine the presence of specific drugs. The antibodies (proteins) combine with the antigens (drugs) or foreign substances if there are drug traces in the urine. It will yield a positive result. If there is no reaction, then the specimen will be considered negative.

If immunoassay is unable to detect any specific drugs, then it may produce false-positive or false-negative results.

  • Gas Chromatography-Mass Spectrometry (GC-MS):  The GC-MS method is generally used to confirm the immunoassay results. It uses more advanced and sensitive methods to produce accurate results. In this method, gas is added to the urine specimen. The gas reacts with the chemical substances in the urine and causes them to split. A mass spectrometer, which is a machine, is used to detect broken compounds.

GC/MS is a standardized method used for follow-up. Sometimes, the liquid is also used to split the compounds in chromatography.

Urine dilution may raise suspicions. It may lead to a failed test or direct towards retest. Drinking significant amounts of water may turn the urine clear and lower the concentration of drug metabolites in the urine. However, a highly diluted urine specimen may be deemed unfit for testing.

Does Taking Diuretics Affect My Drug Test?

Yes, diuretics may impact the drug test if taken regularly. Diuretics are prescription medications to treat certain conditions such as high blood pressure, liver cirrhosis, fluid buildup, etc. Diuretics elevate the excretion of water from the body.

Sometimes, people abuse diuretics to reduce drug concentrations in the urine, thus complicating the detection. Therefore, diuretic screening is also performed using the Methylation and GC/MS method.  The liquid chromatography-tandem mass spectrometry (LC/MS/MS) method is also utilized for direct analysis.

In case you are taking diuretics for any medical condition, you can check with your prescribing physician the effects of it during the drug test and inform the tester before the drug test to avoid any inaccurate test results.

Can I Fail Urine Drug Test Due To Dilution?

Yes, there are possibilities. If you test positive in a diluted drug test sample, the tester will mark it as positive. If the sample tested negative, the tester would recommend either a urine drug screening after few days or mark the specimen as unfavorable for testing and recommend a confirmatory test. A confirmatory test would be performed using another biological sample such as hair follicle or saliva to confirm the presence of drug metabolites. The samples will be collected under direct supervision.

Drug users attempt cheating methods and often get hired with negative dilute. They may get caught if they are randomly tested or under reasonable suspicion.

Summing It Up

Dilution in urine drug tests is not always considered tampering. Certain medical conditions and medications may also induce urine dilution. You may prevent urine dilution by limiting the consumption of water and diuretics before the drug test.

If you are worried about drug traces, you may experiment by performing drug screening at home using the home drug testing kits to prevent embarrassment during the testing process. It would not only save time but also help you to manage when the odds are against you.

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