DRILLING FLUIDS

Subpart 1. Water. Water used for drilling, development, hydrofracturing, sealing, repair, or rehabilitation, other than water from the well or boring itself, must: A. come from a potable water system or from a well or boring of similar use and construction; B. contain a free chlorine residual at all times, except for monitoring wells and remedial wells where chlorine will interfere with water quality analysis or remediation; and C. be conveyed and stored in clean, sanitary tanks and water lines. Subp. 2. Drilling additives. Drilling additives, including bentonite, must meet the requirements of ANSI/NSF Standard 60-2016 as determined by a person accredited by ANSI. A drilling additive is a substance added to the air or water used in the fluid system of drilling a well or boring.