Who does the testing
California law says cannabis must be tested by a licensed lab before it is sold. The lab issues a certificate of analysis (COA), a report of the results.1 The lab tests a sample that stands for a whole batch.2 See how to read a certificate of analysis.
What the lab checks
Every sample must be tested for the items below.2
| What the lab checks | What it means for you | Rule (4 CCR) |
|---|---|---|
| Cannabinoids | How much THC, CBD and similar compounds are in the product. State law names THC, THCA, CBD, CBDA, CBG and CBN.1 | § 15724 |
| Pesticides | Leftover chemicals used to kill pests on the plant. | § 15719 |
| Solvents and processing chemicals | Leftovers from making extracts, oils and vape liquids. | § 15718 |
| Heavy metals | Four metals: cadmium, lead, arsenic and mercury. Products you inhale have lower limits for some of them. | § 15723 |
| Microbial impurities | Germs. Every product is checked for Salmonella and a harmful type of E. coli. Products you inhale are also checked for four kinds of Aspergillus mold. | § 15720 |
| Mycotoxins | Poisons made by some molds. | § 15721 |
| Moisture and water activity | Too much water lets mold grow. Dried flower passes at 0.65 water activity or lower. Solid edibles pass at 0.85 or lower. | § 15717 |
| Foreign material | Things that should not be there, like sand, soil, mold, insect parts or hair. | § 15722 |
| Terpenoids | The compounds behind smell and flavor. Tested only if they apply or are requested. This is not a pass/fail safety test. | § 15725 |
How close the THC number must be
For edibles, the THC in each serving must be within 10% of 10 mg.1 So a 10 mg serving should test between 9 and 11 mg.
What testing does not tell you
- Testing checks a sample, not every package. The sample is meant to represent the batch.2
- Passing means the sample met state limits on the day it was tested. It is not a promise that the product carries no risk.
- Tested products can still be recalled. The Department of Cannabis Control (DCC) posts recalls, including mandatory recalls it orders when there is an immediate and serious threat to life or health.3 Some recent recalls were for mold. See current alerts and recalls.
- Hemp products follow different rules for now. DCC says that starting January 1, 2028, hemp products that can get you high must be made, tested and sold just like licensed cannabis. DCC is still writing those rules.4 See hemp, delta-8 and THCA in California.
Rules may change
DCC updated the limits in its pesticide testing rules. The new limits took effect on October 1, 2026.5 This page does not list pesticide limits. We will update it when the testing rules change again.