Part 5, Subpart 5-1 Standards for Water Wells - Appendix 5B

2. Sand or gravel Clay, hardpan, till, silt, or similar material to depth of more than 15′ 5′ below pumping level 3 Casing size plus 2″ if pressure placement of grout is used,
Casing size plus 4″ if gravity placement of grout is used. 4,5,6 Upper drillhole shall be kept at least one-third filled with clay slurry while driving permanent casing; after casing is in the permanent position, annular space shall be filled with grout 5 2″ minimum Does not apply 2″ minimum 3. Sand or gravel Clay, hardpan, till, silt, or similar material containing layers of sand or gravel within 15′ of ground surface. 5′ below pumping level 4 Casing size plus 2″ if pressure placement of grout is used,
Casing size plus 4″ if gravity placement of grout is used. 4,5,6 Annular space around casing shall be filled with grout. 2″ minimum Does not apply 2″ minimum 4. Creviced, shattered or otherwise fractured shale, limestone, igneous, metamorphic or similar rock types or sandstone Unconsolidated caving material, chiefly sand or sand and gravel to a depth of 19′ or more. Through caving overburden None required Casing shall be firmly seated in rock. Grouting not required. 6″ minimum 6″ preferred Does not apply