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Ohio Monitoring Well Sealing and Abandonment Requirements

When and how to properly abandon monitoring wells in Ohio. OAC 3745-9-03 requirements, sealing procedures, ODNR reporting, and liability considerations.

Published March 29, 2026 10 min read

Overview

Monitoring wells that are no longer in use or are damaged beyond repair must be properly sealed in Ohio. An improperly abandoned well is an open conduit between the surface and the aquifer - it can allow surface contaminants to reach groundwater, let poor-quality water from one zone contaminate another, and create a physical hazard. Ohio EPA has been actively enforcing well abandonment requirements, and property owners with unabandoned monitoring wells face potential notices of violation and mandatory abandonment plans.

Monitoring well sealing requirements are found in OAC 3745-9-03 and the Ohio EPA Technical Guidance Manual for Hydrogeologic Investigations and Ground Water Monitoring (TGM Chapter 9). The ODNR Division of Water Resources maintains the well log and sealing report database.

When a Well Must Be Sealed

Under OAC 3745-9-03, a monitoring well must be sealed when:

  • The well is damaged or deteriorated and will not be repaired to meet construction standards
  • The well is no longer being used for its intended purpose

There is no grace period. If a monitoring well is not actively being used for groundwater monitoring or data collection, and there are no plans to use it, it should be sealed. Wells left in the ground after a project ends, after corrective action reaches NFA, or after a property changes hands are all candidates for abandonment.

Who Can Seal a Well

Well sealing should be performed by qualified personnel familiar with the well construction, site geology, and sealing procedures described in TGM Chapter 9. For monitoring wells installed under BUSTR or VAP programs, the sealing should be done by or under the supervision of an environmental consultant experienced in well decommissioning.

For private water wells (potable wells), Ohio law requires that sealing be performed by a contractor registered with the Ohio Department of Health under OAC 3701-28-18.

Regulatory Framework

Multiple Ohio agencies have authority over different types of wells:

  • Monitoring wells: Ohio EPA Division of Drinking and Ground Waters (DDAGW) enforces OAC 3745-9-03. The agency or program that required the well installation may also have specific requirements.
  • Private water wells: Ohio Department of Health and local health departments enforce sealing requirements under OAC 3701-28-07.
  • Public water supply wells: Ohio EPA DDAGW enforces OAC 3745-9-10.

For environmental monitoring wells installed under BUSTR or VAP, OAC 3745-9-03 is the primary rule. Unless the specific regulatory program (BUSTR, VAP, or another agency) has its own sealing requirements, the procedures in TGM Chapter 9 apply.

Sealing Procedures

TGM Chapter 9 provides detailed guidance on sealing procedures. The general approach involves:

Planning

Before sealing a well, review:

  • Well construction records (casing material, diameter, depth, screen interval, annular seal)
  • Analytical data for soil and groundwater at the well location
  • Hydrogeologic conditions (multiple aquifers, confining layers, contamination zones)
  • Current condition of the well (total depth, siltation, structural integrity)

General Sealing Steps

  1. Remove all obstructions from the well, including pumps, equipment, drop pipes, and debris
  2. Determine the well’s current condition - measure total depth, check for collapse or blockage
  3. Select appropriate sealing materials based on well construction and site conditions. The most common sealing material is neat cement grout or bentonite grout. The choice depends on the hydrogeologic setting and whether multiple water-bearing zones are present.
  4. Place sealing material from the bottom of the well upward, filling the entire borehole. The method of placement (tremie pipe, pouring, pumping) depends on the well depth and diameter.
  5. Remove the surface casing to a minimum depth below the ground surface (typically 2-3 feet). Alternatively, the casing may be cut below grade.
  6. Fill the remaining void to the ground surface with clean soil or other appropriate material.
  7. Restore the ground surface to match surrounding grade.

Special Considerations

  • If the well penetrates multiple aquifers separated by confining layers, the sealing must prevent cross-contamination between zones.
  • If the well is in a contaminated area, the sealing material must be compatible with the contaminants present.
  • If the well construction details are unknown, a more conservative sealing approach should be used.
  • Flush-mount wells require excavation to access the protective casing before sealing can begin.

ODNR Reporting

A well sealing report must be submitted to the ODNR Division of Water Resources within 30 days of completing the sealing, in accordance with ORC 1521.05(C). The online filing process through ODNR’s website is the preferred method.

The sealing report documents:

  • Well location and identification
  • Original well construction details (if known)
  • Sealing materials used
  • Sealing method and procedure
  • Date of sealing
  • Name and contact information of the person who performed the sealing

Submit the sealing report even if the well does not appear in ODNR’s database. Many monitoring wells, particularly older ones, were never properly logged with ODNR when installed.

VAP Considerations

In November 2016, the VAP issued Technical Guidance Compendium VA30011.16.001 specifically addressing the abandonment of monitoring wells. For VAP properties:

  • The CP should account for all wells installed at the site and determine their status (active, not in use, damaged, or abandoned)
  • Verify that all previously abandoned wells were properly sealed and that sealing reports were filed with ODNR
  • Any wells that are damaged or not in use should be properly abandoned before or as part of the NFA process

Unabandoned monitoring wells are considered fixtures of the property and represent a potential environmental liability to the owner.

BUSTR Considerations

For BUSTR corrective action sites:

  • Monitoring wells installed during the Tier 1/2 investigation may need to remain in place during the monitoring period following corrective action
  • After BUSTR issues NFA status, any monitoring wells no longer needed should be properly sealed
  • Wells destroyed during IRA excavation activities do not require sealing reports, but the destruction should be documented in the IRA report
  • If a well sealing report is submitted to ODNR demonstrating proper abandonment, BUSTR will no longer consider that well an existing drinking water source during the drinking water determination

Enforcement

Ohio EPA DDAGW has been actively identifying and enforcing monitoring well abandonment requirements. If a property is found to have unabandoned monitoring wells, the owner may receive a Notice of Violation (NOV) requiring:

  • Submission of a Well Location and Abandonment Plan within 45 days
  • Documentation of all reasonable efforts to locate and seal the wells, which may include geophysical surveys and exploratory excavations
  • A report documenting the abandonment efforts

If a well cannot be located or is impractical to abandon (for example, if it has been covered by a building), the report must evaluate the potential for contaminant migration through the improperly abandoned well.

Source

OAC 3745-9-03: Monitoring Well Requirements. OAC 3745-9-10: Abandoned Well Sealing. Ohio EPA TGM Chapter 9: Sealing Abandoned Monitoring Wells and Boreholes. ORC 1521.05: Well Log and Sealing Report Requirements. Ohio EPA VAP Technical Guidance Compendium VA30011.16.001.