Last Updated 07/23/2026
The City of New London has enacted a Stormwater Ordinance in order to establish minimum stormwater management requirements and controls to protect and safeguard the general health, safety, and welfare of the public residing in watersheds within this jurisdiction. The City of New London is the permitting authority for all land disturbing activities and requires the land owner to maintain all on-site stormwater control facilities and all open space areas (e.g. parks or “green” areas) required by the approved stormwater control plan. The City of New London will only provide construction permits to projects that establish a plan to manage stormwater runoff occurring during the construction process. The City of New London, under the NPDES program, also has the authority to inspect properties for noncompliance and can issue a notice of violation (NOV) for any deficiency or infraction onsite. Property owners are responsible for the maintenance of any stormwater facilities or practices located on the property. The City of New London has the authority to inspect stormwater facilities and practices in order to ascertain that they are properly maintained and functioning.
The City of New London has been issued a “General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems” by Connecticut Department of Energy & Environmental Protection (CTDEEP). The permit is issued to ensure the City of New London is compliant with the requirements of EPA’s Clean Water Act (CWA) for municipalities and the developed areas within them.
The City of New London has created a Stormwater Management Plan, and prepares an annual report to be submitted to CT DEEP to demonstrate compliance with the permit and stormwater management plan. There are six minimum control measures for the plan:
- Public Education and Outreach on Stormwater Impacts
- Public Involvement and Participation
- Illicit Discharge Detection and Elimination
- Construction Site Stormwater Runoff Control
- Post-construction Stormwater Management in New Development and Redevelopment
- Pollution Prevention and Good Housekeeping for Municipal Operations
The annual report, submitted July 16, 2014, highlights each of these measures and explains what the City has been doing for each minimum measure. At this time the city of New London does not have an ordinance for the discharge of stormwater, but zoning regulations and the stormwater plan are the mechanisms that drive compliance with the permit. Developed areas that disturb more than or equal to 1 acre are required to have stormwater controls in place, and the property owner is responsible for an adequate long-term operations and maintenance plan for the BMPs installed onsite.
ZONING REGULATIONS OF THE CITY OF NEW LONDON
ARTICLE VI – SUPPLEMENTARY REGULATIONS
AMENDED TO SEPTEMBER 15, 2014
C. Design, Layout and Location
Drainage – In addition to the requirements of other sections of these regulations, the use of on-site natural filtration functions is encouraged as part of currently accepted Best Management Practices in the reduction of sediment and pollutants. Additionally; drainage shall not be directly channeled to wetlands or watercourses through new piping, flow though natural existing drainage systems shall be maintained as much as possible, and shall not result in a net increase of runoff from the site for the 25-year storm. Also, for previously undeveloped sites, the stormwater management system shall include the retention and filtration of the first inch of runoff from impervious surfaces (excluding roofs).
20) Stormwater Drainage
a) Parking areas shall be graded and drained to dispose of all surface water in accordance with sound engineering principles.
b) No storm water drainage shall be allowed to cross any sidewalk area or public streets.
c) Drainage shall be designed by a professional engineer licensed in the State of Connecticut.
d) The commission shall require that a stormwater management plan is submitted for all proposed parking lots consisting of twenty-five (25) or more parking spaces. However, the Commission may require a stormwater management plan for any proposal if it determines that the site disturbance and proposed use may cause significant nonpoint source pollution. The stormwater management plan shall provide, but not be limited to at a minimum the following information: (The City’s Office of Development and Planning (ODP) has been charged with the responsibility to prepare a recommended format for stormwater management plan submissions to the Commission under these regulations. All applicants are encouraged to consult with ODP staff prior to application submission.)
- Soil characteristics including soil types, hydrologic soil group, and depth to bedrock and groundwater where necessary.
- DEP ground/surface water quality classification of the site.
- Location and description of all proposed best management practices (BMPs) both for construction activities and post-construction long-term nonpoint source pollution control.
- Proposed maintenance and operation manual or schedule for any stormwater control methods.
- Hydrologic analysis and calculations of stormwater runoff rates and water quality pollutant concentrations including suspended solids removal rates for pre and post development.
- To the extent practicable, maintain post-development peak runoff rate and average volume at levels that are similar to pre-development levels and reduces post-development average annual total suspended solid (TSS) loads by 80%.
e) Stormwater management systems shall be designed and maintained to manage site runoff in order to prevent flooding, control peak discharges where required, and maximize retention and water quality treatment on-site.
f) On proposed sites with discharges of stormwater within five-hundred (500) feet of coastal waters, the stormwater management system shall be designed to retain and treat the volume generated by the first one (1) inch of rainfall unless a demonstration can be made that specific site constraints prevent meeting this goal. In such case, the stormwater management system should be designed to retain and treat the maximum amount that is technically feasible.
Inland Wetlands & Watercourses Regulations of the City of New London – Amended January 23, 2012
Any development activity occurring in this area is subject to more stringent standards. The map of regulated areas delineates the general location and boundaries of inland wetlands and the general location of watercourses. The link to these regulations is at the bottom of the page.
New London Stormwater Management Plan
This Stormwater Management Plan (SMP) was developed by the City of New London to protect water quality and reduce the discharge of pollutants from the municipality’s storm sewer system to the maximum extent practicable (MEP). This SMP addresses the requirements established by the CT Department of Energy and Environmental Protection’s (DEEP) General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems (MS4 General Permit). This permit is the local enforcement mechanism of the U.S. Environmental Protection Agency’s (EPA) National Pollutant Discharge Elimination System (NPDES) Stormwater Phase II Rule. SMP Structure The plan outlines a program of best management practices (BMPs), measurable goals, responsible individuals or departments, and implementation schedules for the following six minimum control measures:
(1) Public education and outreach
(2) Public involvement and participation
(3) Illicit discharge detection and elimination
(4) Construction site stormwater runoff control
(5) Post-construction stormwater management in new development and redevelopment
(6) Pollution prevention/good housekeeping
In developing this legal authority, the City will consider the following watershed protection elements to manage the impacts of stormwater on receiving waters:
- Minimize the amount of impervious surfaces (roads, parking lots, roofs, etc.) within each municipality by minimizing the creation, extension, and widening of parking lots, roads, and associated development and encourage the use of Low Impact Development or green infrastructure practices.
- Preserve, protect, create and restore ecologically sensitive areas that provide water quality benefits and serve critical watershed functions. These areas may include, but are not limited to; riparian corridors, headwaters, floodplains and wetlands.
- Implement stormwater management practices that prevent or reduce thermal impacts to streams, including requiring vegetated buffers along waterways, and disconnecting discharges to surface waters from impervious surfaces such as parking lots.
- Seek to avoid or prevent hydromodification of streams and other water bodies caused by development, including roads, highways, and bridges.
- Implement standards to protect trees, and other vegetation with important evapotranspirative qualities.
- Implement policies to protect native soils, prevent topsoil stripping, and prevent compaction of soils.
- Coordinate with state or local health officials to ensure no interference with performance of on-site septic systems.
- Limit turf areas.
In addition, the City will review its current regulations – site planning requirements, zoning regulations, street design regulations, and infrastructure specifications with minimum size criteria for impervious cover (roads, parking lots, etc.) to identify and, where appropriate, reduce or eliminate existing regulatory barriers to implementation of LID and runoff reduction practices to the MEP.
5.2 Enforce LID/runoff reduction requirements for development and redevelopment projects
The City will enforce the LID and runoff reduction requirements defined in Section 5.1 for development and redevelopment projects.
5.3 Implement long-term maintenance plan for stormwater basins and treatment structures
The City will develop a maintenance plan for retention / detention ponds and stormwater treatment structures that it owns or over which it holds an easement or other authority and that are located in the City’s priority areas to ensure their long-term effectiveness. This plan will require an annual inspection of those retention / detention ponds and stormwater treatment structures and removal of accumulated sediment and pollutants in excess of 50% design capacity.
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Frequently Asked Questions
What size parking lot triggers a stormwater management plan requirement in New London?
Twenty-five or more parking spaces. The Commission requires a stormwater management plan submission for any proposal at or above that threshold, and can require one for smaller projects too if it determines the site disturbance or proposed use could cause significant nonpoint source pollution.
What does New London's stormwater management plan actually need to include?
Quite a bit: soil characteristics and hydrologic group, the DEEP water quality classification for the site, a description of proposed best management practices for both construction and long-term post-construction control, a maintenance and operation schedule, and hydrologic calculations comparing pre- and post-development runoff rates and pollutant concentrations.
Is there a specific pollutant reduction target for New London developments?
Yes. To the extent practicable, developments have to maintain post-development peak runoff rate and volume similar to pre-development levels, and reduce post-development average annual total suspended solids loads by 80%.
Does New London have extra stormwater requirements for properties near the coast?
Yes. Sites discharging stormwater within 500 feet of coastal waters have to design their system to retain and treat the volume from the first inch of rainfall, unless site-specific constraints make that impossible, in which case the design has to retain and treat the maximum amount technically feasible.
Can I direct my property's drainage straight into a wetland or watercourse in New London?
No, not through new piping. Drainage can’t be directly channeled to wetlands or watercourses that way, and flow through existing natural drainage systems has to be maintained as much as possible without causing a net increase in runoff for the 25-year storm.
Who has to design my stormwater drainage system in New London?
A professional engineer licensed in the State of Connecticut. That requirement applies specifically to stormwater drainage design under the city’s supplementary zoning regulations, and parking areas separately have to be graded and drained according to sound engineering principles with no runoff crossing sidewalks or public streets.
Does New London inspect stormwater basins and treatment structures it owns?
Yes, on an annual basis, for those it owns or holds an easement over in priority areas. That maintenance plan requires removing accumulated sediment and pollutants once a basin or structure exceeds 50% of its design capacity, keeping it well short of full failure before triggering cleanup.
Does building in a New London wetland or watercourse area come with extra requirements?
Yes, and they’re more stringent than standard zoning. Any development activity in a mapped inland wetland or watercourse area falls under a separate set of regulations with tighter standards, so it’s worth checking that map before assuming standard zoning stormwater rules are all that apply.
How can AQUALIS help my property stay compliant with New London's stormwater requirements?
AQUALIS helps New London property owners prepare the stormwater management plans required for parking lots of 25 spaces or more, design systems that meet the city’s 80% TSS reduction target and coastal retention standards, and navigate the added requirements that apply to sites near wetlands or watercourses.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
