- (1) Vibrating wire piezometers shall be sealed using materials as allowed in WAC 173-160-450; or sealing materials as designed and recommended by the manufacturer provided that the material, when placed, provides a permeability of 1 x 10-7 cm/sec or less. The licensed driller or engineer shall provide documentation from the manufacturer demonstrating that the sealing material meets the permeability requirements of this section.
- (2) The use of bentonite products intended for use as drilling fluids, low solids content bentonite mixtures, fly ash, and hydrated lime are prohibited as additives or sealants.
[Statutory Authority: Chapter 18.104 RCW. WSR 09-01-125 (Order 08-10), § 173-160-458, filed 12/19/08, effective 1/19/09.]