“Unofficial comparison” by NID of cannabis growing customers and others raises questions

GRASS VALLEY, Calif. February 12, 2018 – NID’s Water & Hydroelectric Operations Committee (WHO) is one of four standing committees the District uses to vet items before they come to the full Board. Among other items on tomorrow’s agenda, the committee will hear a staff report on “Potential Effects of Cannabis Cultivation on Water Quality & Demand: Review and discuss the proposed regulations and the potential adverse effects of cannabis cultivation on water quality and demand.”

The staff report on the informational item states “The District has conducted an unofficial comparison of treated water customer demand on roughly twenty parcels. Ten parcels contained outdoor cannabis cultivation while the other ten were neighboring parcels without any visible sign of cannabis. On average, water demands for parcels partaking in outdoor cannabis cultivation were 70% higher than the neighboring property without cultivation.

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Informed consent?

The report does not give any indication if the selected customers were informed of the monitoring. The selected parcels are not identified in the staff report, neither those allegedly having had outdoor cannabis cultivation nor the non-growing parcels. No indication is given if the parcels have one or multiple residences, how many people live on any given parcel. Average household size in Nevada County is 2.40, according to the U.S. Census Bureau. Also not quantified are the size of the alleged cannabis grows.

Apples and Oranges?

The 70% higher consumption ascribed to the grow parcels is not expressed in gallons. According to NID’s September 2017 Supplier Conservation report submitted to the State Water Board, the estimated water usage was 254 gallons per day and per person (GPCD). A 70% higher usage equals 431 GPCD. For December 2017, NID reported an 85 GPCD.

“The District’s planning and management documents utilize 1250 gallons per day as the equivalent demand that each treated water connection will consume,” the report continues. At publication time, we were unable to verify this number with NID.

The staff report also states “The use of hydroponics for indoor grows by District customers is a real potential. The practice of growing cannabis utilizing water only (no soil required) leads to the pumping of fertilizers into pressurized water systems to feed the plants. This increases the District’s potential for cross contamination from backflow into drinking water distribution system.” Backflow preventers have been a state requirement for several years now.

The report will be discussed starting at 9:00 am on Tuesday, February 13, 2018 at the NID Board office.