Bentonite drilling fluids used to construct or repair a water-supply well must have a measurable chlorine residual at all times during drilling or repair, except for a remedial well where chlorine will interfere with water quality analysis or remediation.
Minn. R. agency 144, ch. 4725, WATER-SUPPLY WELLS, pt. 4725.4150
Statutory Authority: MS s 103I.101; 103I.111; 103I.205; 103I.221; 103I.301; 103I.401; 103I.451; 103I.501; 103I.525; 103I.531; 103I.535; 103I.541; 103I.621