THC (tetrahydrocannabinol) can be detected in urine for varying lengths of time depending on the frequency and amount of marijuana use:

• One-time or occasional use: THC metabolites are typically detectable in urine for up to about 3 days after use

• Moderate use (around 4 times per week): Detection can last about 5 to 7 days

• Daily or chronic use: THC can be detected for 10 to 15 days after last use

• Heavy or chronic heavy use (multiple times per day): Detection windows can extend to 30 days or more, with some studies showing up to 70 days in extreme cases

The primary metabolite tested in urine is THC-COOH, which appears within 1 to 4 hours after use and can remain detectable for the durations above depending on use patterns

. Factors affecting detection time include the user's metabolism, body fat percentage, frequency of use, potency of the marijuana, and hydration levels

. In summary, urine tests can detect THC metabolites from about 1 day up to over a month, with longer detection times for heavier and chronic users. For a single use, detection is usually up to 3 days, while chronic heavy users may test positive for 30 days or longer