California medical cannabis customers could be losing about 25 percent of their precious bud purchases to poor weights and measures at the register. Now, state regulators are stepping in.

This June, the California Division of Measurement Standards released a brochure for the state’s roughly 2,500 weed shops — telling them to upgrade their scales and prepare for snap inspections.

High-grade medical cannabis can wholesale for up to $5,000 per pound and retail for up to $20 per gram. Low-quality scales can mis-weigh such a tiny bag of pot by a large margin, generating “dramatic overcharges (or undercharges),” the Division states.

“WEIGHING MEDICAL CANNABIS USING A TYPICAL CLASS III GROCERY SCALE COULD RESULT IN AN ERROR OF ± 25%, CAUSING SERIOUS FINANCIAL LOSS TO EITHER BUYER OR SELLER,” it states.

Cannabis buyers should be on the lookout for “Class II” scales, which are 10 times more accurate than Class IIIs. California is in the middle of regulating its multi-billion medical cannabis industry. The California Division of Measurement Standards’ job is, “Ensuring fair competition for industry and accurate value comparison for consumers.”

By 2018, the Division will be performing snap inspections where “The inspector will bring precisely calibrated test equipment such as test weights and volumetric measures to test your scales and packages containing liquid products. The inspector may also test your scale and then use it to verify “net content” during package inspections.”

The new weights rules also apply to “cannabis cultivators, product manufacturers and other persons that package and label the net quantity of cannabis products; … distributors, transporters.”

Effective January 1, 2018, licensed “Weighmasters” will help track and certify the state’s legal crop.

Thanks to regulations, consumers can expect a baseline standard for packaging as well, with requirements from the Division, as well as the California Departments of Public Health, Food and Agriculture, and Consumer Affairs.

More marijuana news from Smell the Truth podcast The Hash

Surviving Marijuana Legalization in California, with Fiona Ma, member California Board of Equalization

