NR 812 Revisions – Annular Space Sealing, Grouting and Well / Drillhole Filling and Sealing

To all licensed drillers and pump installers,

Changes to NR 812 – Wisconsin’s well and pump code - are coming soon!

Revisions to chapter NR 812, Wisconsin Administrative Code (NR 812) are expected to go into effect on July 1, 2020. DNR is sending weekly email communications on specific topics to all drillers and pump installers. This week, we focus on annular space sealing, grouting, and filling and sealing of wells and drillholes.

A short training module on this subject is now available at https://p.widencdn.net/jdz9zs/Annular-Space-Sealing-Filling-and-Sealing-Module

Key changes to annular space sealing, grouting, and well and drillhole filling and sealing:

• Grout densities and use of a mud balance - NR 812.11 addresses Well Construction Equipment and Materials. In this section, grout densities have been added in Table C and in the text of the section. For example:
  • Neat Cement – 15.0-15.8 lb/gal
  • Cement-bentonite – minimum of 13.8 lb/gal
  • Mud and cuttings – minimum of 11 lb/gal

  Also, the driller shall use a mud balance to measure grout density. 

• Increased flexibility for grouting wells terminating in unconsolidated formations - NR 812.13 addresses wells terminating in unconsolidated formations. This section will provide more flexibility for grouting in keeping with the performance-based nature of the revised code.

• Mud and cuttings as an annular space seal - Both NR 812.13 and NR 812.14 will limit the use of mud and cuttings as an annular space seal. These limits apply to all wells, regardless of the formation in which they are constructed. Mud and cuttings will only be allowed for upper enlarged drillholes less than or equal to 20 feet deep. If casing is advanced through an upper enlarged drillhole greater than 20 feet deep, bentonite or cement grouting will be required. 

• Grouting of PVC wells – Grouting of PVC-cased wells is addressed in both NR 812.13 and NR 812.15. PVC casing will only be allowed in wells terminating in unconsolidated formations, and may not be driven or mechanically advanced, so PVC-cased wells must be placed in an upper enlarged borehole. If the well is not a flowing well, cement grout may not be used. If the well is flowing, it must be grouted with neat cement.

• Use of bentonite chips in bedrock wells - NR 812.14 addresses wells terminating in bedrock. NR 812.14(8) outlines a process to use bentonite chips when losing grout to fractures or voids in the formation without requiring a verbal variance. 

• Dual aquifer prohibition and requirements for wells drilled into the Maquoketa Shale - The revised code will more clearly state the prohibition on dual aquifer wells, and construction dealing with the Maquoketa Shale formation:
  • For dual aquifer construction, a well may not be open to both an unconsolidated and a bedrock formation.
  • Any well constructed to withdraw water from an aquifer beneath the Niagara and Maquoketa Shale in the eastern part of Wisconsin shall be cased and grouted into the Maquoketa shale, except where designated by DNR.
• Use of bentonite pellets for wells 3 inches in diameter or less - NR 812.26 addresses filling and sealing of wells and drillholes. Revisions to this section will allow bentonite pellets as a filling and sealing material for wells or drillholes less than 3 inches in diameter. Be advised that the pellets will first require manufacturers to obtain product approval from DNR; no bentonite pellets are currently approved for use in Wisconsin.
• Unused wells must be filled and sealed - NR 812.26 continues to require unused wells to be filled and sealed within 90 days, and will require seasonal and high capacity irrigation wells to be filled and sealed if unused for 3 years.

Make plans now to adjust your construction practices and materials to meet the new requirements. Contact your local DNR Private Water Supply Specialist with any questions.

Where can I get more information?

DNR will send weekly email communications to drillers and pump installers about the rule changes, with more details on specific topics, and links to training modules, publications and fact sheets as they become available. This information will also be posted on DNR’s NR 812 rule changes web page.