Groundwater Protection

This model ordinance establishes a groundwater protection overlay district to safeguard public drinking water supplies sourced from aquifers. The primary goal is to prevent contamination by regulating land uses within delineated protection zones around public water supply wells. The ordinance creates a regulatory framework that is superimposed on a community’s existing zoning, adding specific requirements for properties located within sensitive groundwater recharge areas.

The ordinance is structured around a two-zone system based on the hydrogeologic principle of groundwater time-of-travel (TOT)—the time it takes for a contaminant to travel from a point on the surface to a drinking water well. This risk-based approach creates a highly protective zone immediately surrounding a well and a secondary zone that extends further into the well’s capture area. While the model provides a fundamental structure, jurisdictions can adapt it with more complex delineations, such as the multi-zone system based on two- and ten-year TOT contours used in Hernando County, Florida, to protect the Floridan Aquifer.

Effective Source Water Protection relies on controlling potential pollution at its source. This model provides municipalities with enforceable standards to prohibit high-risk activities near wells and to require specific engineering controls for other land uses, forming a critical component of a comprehensive water resource protection program.

Key provisions

Applicability and Zoning Structure

The ordinance functions as an overlay district, meaning its provisions apply in addition to the regulations of the underlying base zoning districts. It applies to all new construction, reconstruction, or expansion of existing buildings and any new or expanded land uses. The district is divided into two distinct zones based on proximity and groundwater travel time to public water supply wells.

Prohibited and Permitted Uses

The model ordinance establishes a list of prohibited land uses for the most sensitive area, Zone 1, due to the high risk of contamination they pose. Uses not explicitly prohibited may be permitted if they comply with the underlying zoning and meet the ordinance’s performance standards. In Zone 2, all uses permitted in the underlying district are allowed, provided they adhere to the same performance standards.

Performance Standards

For all permitted and special exception uses within either zone, the ordinance mandates a set of performance standards designed to prevent groundwater contamination. These standards represent key engineering and operational controls:

• Secondary Containment: Any facility that collects, handles, stores, or disposes of potentially hazardous liquid or solid materials must have a secondary containment system that is easily inspectable and designed to capture any release from the primary container.
• Underground Storage: Underground tanks or pipes carrying hazardous materials must be double-walled and include inspectable sumps for leak detection.
• Contingency Planning: Facilities must prepare and maintain a contingency plan for preventing contamination in the event of floods, fires, equipment failures, or other emergencies. The plan must address containment of runoff and safe procedures for emergency responders.
• Well Abandonment: All abandoned wells must be properly plugged according to state and local regulations to prevent them from becoming direct conduits for surface contamination to enter an aquifer.

These standards ensure that even legally permitted activities are conducted in a manner that minimizes risk. Design specifications for these systems can be found in the Design Manual.

Administration and Permitting

The ordinance outlines procedures for handling special exceptions and resolving boundary disputes. The expansion of existing nonconforming uses may be allowed as a special exception in Zone 1, but only if the expansion does not pose a greater contamination risk. If the precise location of the overlay district boundary is in question for a specific parcel, the landowner bears the burden of proof to demonstrate the correct boundary. The local government may hire a qualified professional (engineer, geologist, etc.) to make a determination at the landowner’s expense.

Enforcement and Penalties

Enforcement follows a two-track approach. The primary method is civil enforcement, which begins with a complaint and investigation. If a violation is found, the jurisdiction first attempts informal reconciliation with the violator. If the violator fails to take corrective action within a specified timeframe, the jurisdiction may undertake the necessary corrections and bill the violator for the costs.

In lieu of the civil process, the ordinance allows for criminal enforcement. A violation is classified as a misdemeanor, punishable by fines and/or imprisonment. This dual system provides flexibility, encouraging voluntary compliance while retaining the authority to impose penalties for significant or willful violations.

Selected provisions, annotated

The purpose of the Groundwater Protection Overlay District is to protect public health and safety by minimizing contamination of shallow/surficial aquifers and preserving and protecting existing and potential sources of drinking water supplies.

Model Groundwater Ordinance, Purpose and Intent

This statement establishes the legal basis for the ordinance. By defining the protection of public health as the primary goal, it provides a strong foundation for implementing land use regulations that are more restrictive than those in the underlying zoning districts.

Zone 1 is defined as the area within the 6-month time-of-travel distance mapped around all the public water supply well(s).

Model Groundwater Ordinance, Zones

This provision links the regulatory boundary of the most critical protection zone to a scientific, hydrogeologic standard rather than an arbitrary distance. Using time-of-travel allows the zone’s shape and size to reflect actual groundwater flow patterns, providing a more technically defensible basis for regulation.

Any facility involving the collection, handling, manufacture, use, storage, transfer or disposal of any solid or liquid material or wastes…must have a secondary containment system which is easily inspected…

Model Groundwater Ordinance, Performance Standards

This requirement is a core engineering control of the ordinance. It shifts the focus from simply prohibiting uses to requiring specific, verifiable technology to mitigate risk for permitted activities. Secondary containment acts as a crucial failsafe to prevent a leak or spill from becoming a contamination event.

Nothing in this ordinance shall be construed to imply that the local government has accepted any of an owner/developer’s liability if a permitted facility or use contaminates groundwater in any aquifer.

Model Groundwater Ordinance, Liability

This is a standard but critical legal provision. It clarifies that obtaining a permit and complying with the ordinance’s standards does not absolve a property owner or operator of legal and financial responsibility should their activities result in groundwater contamination.

What makes it a useful model

This model ordinance provides a clear and legally defensible framework for protecting critical drinking water sources. Its primary strength lies in the risk-based zoning approach, which creates protection areas based on scientific principles of groundwater movement. This time-of-travel concept is more robust than using simple fixed-radius buffers, as it accounts for local geology and hydrology. The two-zone structure is scalable, allowing a community to start with a straightforward system that can be refined with more detailed hydrogeologic data over time.

The ordinance effectively balances prohibition with mitigation. While it strictly prohibits the highest-risk land uses in the most vulnerable areas, it also establishes clear performance standards for permitted activities. This focus on engineering controls like secondary containment and spill prevention planning provides a practical pathway for compatible economic development to occur within the protection district. This approach is central to most modern Source Water Protection programs, which aim to manage risk rather than halt all development.

Finally, the document is designed for adaptation. It contains placeholders for the specific authorities, timelines, and penalties that a municipality must define. It also includes essential administrative and legal clauses covering enforcement, boundary disputes, liability, and severability, making it a comprehensive starting point for any community seeking to develop its own regulations. More examples of locally adapted ordinances can be found in the Model Ordinances library.

Adaptation checklist for municipalities

Before adopting a groundwater protection ordinance, a local government must tailor the model language to its specific legal, administrative, and hydrogeologic context. The following actions are essential for successful implementation:

• Identify and map all public water supply wells and their corresponding recharge areas.
• Engage a qualified hydrogeologist to delineate the time-of-travel zones (e.g., 6-month, 2-year, 10-year) that will serve as the legal boundaries for the overlay district.
• Incorporate the finalized Groundwater Protection Overlay District map into the official municipal zoning map.
• Customize the lists of prohibited, permitted, and special exception uses for each zone to reflect local land use patterns and specific risks.
• Designate the specific municipal department or official (e.g., Planning Board, Zoning Administrator, Groundwater Protection Coordinator) responsible for administration and enforcement.
• Establish specific numeric thresholds for performance standards, such as the quantity of petroleum products that triggers secondary containment requirements.
• Define the required contents and review process for facility contingency and spill response plans.
• Set the specific time periods for the civil enforcement process (e.g., “30 days”) and the exact fines and penalties for criminal enforcement.
• Develop and adopt a fee schedule to cover the costs of permit review, site inspections, and administration.
• Ensure the ordinance is consistent with other local regulations, including those for Stormwater Management and Illicit Connections.
• For communities in karst terrain, add specific provisions for vulnerable features like sinkholes, similar to those in a dedicated Sinkhole Protection ordinance, to prevent direct conduits for contamination.
• Review and cross-reference all state and federal regulations governing hazardous materials, underground storage tanks, and wellhead protection to ensure local rules are compliant and not pre-empted.