7.6 Outdoor Lighting

7.6.A Purpose

These regulations are intended to provide specific standards for lighting in order to maximize the effectiveness of site lighting, to enhance public safety and welfare, to raise public awareness of energy conservation, to avoid un-necessary upward illumination, indirect lighting and illumination of adjacent properties, and to reduce glare.

7.6.B Applicability

Except as herein provided, these regulations shall apply to any outdoor lighting fixtures installed, modified, refurbished, repaired or serviced on private property within the City of Groton.

All businesses, and community roadways, sidewalks and town property luminaires should be planned and installed with the idea of being a "good neighbor" by keeping unnecessary direct light from shining onto abutting lots or roadways, both public and private.

7.6.C Standards


  • All exterior lights and sign illumination shall be designed, located, installed and directed in such a manner as to:
    • Prevent direct or objectionable glare, light trespass, spill light, or obtrusive light;
    • Be shielded (full cut off);
    • Employ soft, transitional light levels which are consistent from area to area;
    • Minimize contrast between light sources, lit areas and dark surroundings; and
    • Be confined within the target area.
  • In all non-residential districts and in all areas adjacent to a residential lot, no externally-mounted direct light source shall be visible at the lot line at ground level or above. The direct illumination measured at the lot line shall be zero (0.0) foot-candles, excluding driveway entrances.
  • Lighting designed to highlight flagpoles shall be low level (no more than 100 watt incandescent equivalent) and shall be targeted directly at the flag.
  • Lighting shall include timers, dimmers and/or sensors to reduce unnecessary light level during non-business hours to a minimum level required for overnight security.
  • The height of luminaries, except streetlights in public right-of-ways, shall be the minimum height necessary to provide adequate illumination, but shall not exceed a height of eighteen (18) feet. The height of a luminaire shall be measured from the finished grade (not the top of a supporting concrete base) to the bottom of the luminaire.
  • Light standards within a parking lot shall be located within landscaped islands or buffer strips, and shall be set back two feet from any parking space unless wheel-stops are provided.


  • In reviewing and approving outdoor lighting, the Commission may utilize recommendations for lighting levels as issued by the Illuminating Engineering Society of North America, the International Dark-Sky Association, or other reference.
  • The use of utility poles for outdoor lighting is prohibited.
  • Any light determined by the Zoning and Building Official and/or City Planner to be obtrusive, spill light, upward lighting, light trespass, or otherwise not in compliance with these regulations shall constitute a violation.
  • A photometric survey shall be submitted as part of any site plan that demonstrates compliance with these standards. Such photometric survey shall show both business hour and non-business hour lighting plans.

7.6.D Exemptions & Modifications

  • Temporary holiday lighting is exempt from these Regulations, for a period of time to be commensurate with the holiday being celebrated, but in no event shall such lighting at a commercial property exceed a duration of 45 days annually in the aggregate.
  • Temporary lighting used by the Police Department, Fire Department or emergency services is exempt from these Regulations.
  • The Commission may, by special permit, allow lighting that does not comply with the requirements of this Section provided the Commission determines, in its sole discretion, that such proposed lighting is consistent with the purpose of these Regulations. The following considerations are provided as guidance:
    • That an extraordinary need for security exists because of a history of vandalism or other objective means;
    • That in traveled ways or areas, conditions hazardous to the public exists, such as steep embankments or stairs;
    • That it would be unreasonable to require replacement of an entire lighting installation because a minor change is proposed to an existing non-conforming lighting installation;
    • Special lighting is indicated for historic buildings;
    • That ornamental up-lighting of sculpture, buildings or landscape features end enhance the character of the area; and
    • Such lighting is necessary for special outdoor events and playing fields.
  • The Commission may modify the requirements of Section 7.6.C for a temporary use approved under these Regulations.