Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5299 – Standard Test Method Technical Guide
The ASTM D5299/D5299M‑18 standard provides a comprehensive guide for the permanent decommissioning (closure) of groundwater wells, vadose zone monitoring devices, boreholes, and other associated equipment used in environmental activities. This guide is essential for mitigating subsurface risks associated with solid and hazardous waste sites.
🎯 Scope and Applicability
This standard covers procedures specifically related to the permanent closure of devices where solid or hazardous materials or wastes are identified. The following devices are explicitly considered in the guide:
- Boreholes used for geoenvironmental purposes.
- Monitoring and observation wells.
- Injection wells and extraction wells (for contaminated groundwater, floating contaminants like gasoline or tetrachloroethylene, or soil gas).
- Piezometers and any other well or boring housing a vadose zone monitoring device.
Most monitoring wells addressed by this guide are relatively small, with typical diameters ranging from 2.5 to 20 cm [1 to 8 inches]. The standard explicitly states that temporary decommissioning is not covered (Section 1.2).
⚠️ Regulatory Advisory: While this guide provides the standard methodology, it is critical to consult and follow national, state, or local regulations, as these may control required decommissioning procedures (Note 1). Furthermore, detailed guidance for multiple-screened wells is not provided, although methods such as overdrilling may be adapted (Note 3).
| 🟦 Device Category | 📏 Typical Application (from Standard) | ⚡ Related Context |
|---|---|---|
| Monitoring / Observation Wells | Water quality sampling, water level observation, soil gas sampling | Typically 2.5–20 cm [1–8 in] in diameter |
| Injection / Extraction Wells | Removal of floating/submerged contaminants (gasoline, PCE) or soil gas extraction | Covered for informational guidance (Note 2) |
| Piezometers / Vadose Zone Devices | Water level measurement / unsaturated zone monitoring | Constructed in a manner similar to a well |
| Geoenvironmental Boreholes | Subsurface investigation and monitoring device housing | Primary focus for hazardous waste site closure |
⚙️ Decommissioning Objectives and Rationale
The guide establishes five distinct objectives (Section 1.3) driving the necessity for proper permanent decommissioning. These focus on eliminating direct pathways for contaminant migration and ensuring the long-term integrity of the subsurface.
| 🎯 Objective | ⚡ Mandated Requirement (D5299 Section 1.3) |
|---|---|
| Eliminate Misuse | Ensure the well cannot be used for purposes beyond its original environmental monitoring intent (1.3.1). |
| Prevent Contaminant Migration | Stop migration into an aquifer, between aquifers, or within the vadose zone (1.3.2, 1.3.3). |
| Block Fluid Pathways | Reduce or eliminate the potential for vertical and horizontal migration of fluids in or adjacent to the wellbore (1.3.4). |
| Retire from Active Service | Remove wells that are structurally failed, cannot be rehabilitated, are no longer needed, or provide unreliable data (1.3.5). |
💡 Extended Applicability: Although primarily intended for hazardous waste sites, this guide can also be applied to decommissioning boreholes where non-hazardous pollutants (such as nitrates or sulfates) are present, or when routine geotechnical studies indicate unforeseen contamination (Note 1).
🛡️ Regulatory Compliance and Best Practices
Adherence to this guide requires a strong understanding of the local regulatory framework. The standard serves as a best-practice technical foundation, but local requirements must always be consulted for specific sealing materials, placement depths, and reporting obligations. The term “well” in this guide broadly denotes monitoring wells, piezometers, and other devices constructed in a similar manner unless specifically distinguished (Note 2).
❓ Frequently Asked Questions
🔍 What types of devices are explicitly covered by ASTM D5299?
The standard covers permanent decommissioning of boreholes for geoenvironmental purposes, monitoring wells, observation wells, injection wells, extraction wells, piezometers, and any borehole housing a vadose zone monitoring device (Section 1.1).
💡 Does D5299 cover temporary decommissioning or only permanent closure?
The guide explicitly covers only permanent decommissioning (closure). Temporary decommissioning procedures are not covered by this standard (Section 1.2).
⚡ What are the main objectives for decommissioning a monitoring well?
The five objectives are: eliminating misuse, preventing contaminant migration (into/between aquifers and the vadose zone), reducing vertical/horizontal fluid migration, and removing structurally failed or unreliable wells from service (Section 1.3).
📌 What is the typical size range for wells considered in this guide?
The guide notes that most monitoring wells are relatively small in diameter, typically 2.5 to 20 cm [1 to 8 inches], which directly influences the decommissioning methods and materials discussed (Section 1.3).