Antrim Sewage Lagoons Reservoir Report
Last Updated: December 19, 2025
The Antrim Sewage Lagoons in Hillsborough, New Hampshire, are owned and regulated by the local government and fall under the jurisdiction of the NHDES Dam Bureau.
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Summary
Completed in 1978, these earth dams serve a primary purpose of wastewater management and have a storage capacity of 19.4 million gallons. The lagoons cover a surface area of 2.63 acres and have a maximum dam height of 13 feet.
Despite being classified as having a significant hazard potential, the Antrim Sewage Lagoons are in satisfactory condition as of the last assessment in July 2016. Regular inspections are conducted, with the most recent one in April 2020, and the facility meets state permitting and inspection requirements. While the lagoons do not have a spillway, they are designed to effectively manage wastewater and mitigate any potential risks associated with their operation.
Water resource and climate enthusiasts interested in the intersection of infrastructure and environmental impact would find the Antrim Sewage Lagoons an intriguing case study. With a high risk assessment rating and a history dating back to the late 1970s, this facility showcases the importance of proper maintenance and regulatory oversight in managing water resources effectively.
Year Completed |
1978 |
Dam Length |
1150 |
Dam Height |
13 |
River Or Stream |
NA |
Primary Dam Type |
Earth |
Surface Area |
2.63 |
Nid Storage |
19.4 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
13 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Antrim Sewage Lagoons
Gregg Lake boat launch