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“Healthy Lawns, Clean Water” Fertilizer Reduction Program

In response to environmental and public health concerns attributed to excess nitrogen, Suffolk County Local Law No. 41-2007 was passed to reduce nitrogen pollution to our groundwater and surface waters through the overall reduction and better management of fertilizer applications. Nitrogen pollution occurs when excess nitrates in fertilizers not taken up by plant roots runoff from lawns and roadways into our waterways or leach below plant root levels and into our groundwater. Too much nitrogen can cause excessive algae growth in surface waters which interferes with recreational activities like boating, fishing, and swimming, changes the natural ecology of our waters, and is detrimental to the environment. Elevated concentrations of nitrates in our natural underground aquifers, the sole source of Suffolk County’s drinking water, can potentially cause serious health problems for humans and animals.

Suffolk County launched the comprehensive “Healthy Lawns, Clean Water” campaign to convey the aspects of Suffolk County Local Law No. 41-2007 to the public.

Elements of the Healthy Lawns, Clean Water program include:

  • A countywide ban on fertilizer application to turf grass between November 1 and April 1. The potential for fertilizer runoff into surface water and leaching into groundwater is greatest during this time, as the grass is not actively growing and unable to absorb the nutrients.
  • A ban on the use of fertilizer on County owned properties (exceptions: golf courses, athletic fields, the Suffolk County Farm, and new turf along public works projects).
  • The development of best management practices for County golf courses, athletic fields, and the Suffolk County Farm.
  • A requirement that all licensed landscapers take a Fertilizer Turf Management Course, which teaches the proper use and application of fertilizers and best management practices for lawn maintenance.
  • A requirement for retail establishments to post signs and brochures, supplied by Suffolk County, to advise consumers about the risks of nitrogen-based fertilizers and provide them with information on the proper use and application of such products.
  • Periodic inspections of retail establishments to insure compliance with the posting requirement.
  • An educational website for homeowners and landscapers on environmentally responsible lawn care:
  • An annual reporting requirement on fertilizers sold in Suffolk County to track trends in sales and usage of fertilizer products.

Through its multi-faceted Healthy Lawns, Clean Water program, Suffolk County is taking a proactive approach to minimize the harmful effects of nitrogen pollution on our precious ground and surface waters. With the support of our residents, this effort to keep fertilizers out of our waters can have a significant impact on the health of both Suffolk’s citizens and our environment.

Any questions regarding the Nitrogen Fertilizer Reduction Law can be directed to Michael at

To learn more about the Healthy Lawns Clean Water program please visit the website at:

To view Frequently Asked Questions (FAQs) Click Here

Suffolk County Nitrogen Fertilizer Turf Management Course

The Department will be holding a virtual course on
Tuesday, September 12th, 2023 at 9:00am – 12:00pm.

Call or Email Jennifer to register at
631-853-4412 or

A $10 Registration fee must be mailed to Cornell Cooperative Extension and certificates will be mailed once your payment is received.

Please make personal checks out to Cornell Cooperative Extension of Suffolk County and mail to:
Cornell Cooperative Extension
423 N Griffing Ave # 100
Riverhead, NY 11901
ATTN: Tamson Yeh

Landscapers need to take this class one time only.
If you have taken the class and have not received your certificate please call the County. (Please allow 2-3 weeks for processing.) There is no need to attend another class.

Suffolk County Government

H. Lee Dennison Bldg

100 Veterans Memorial Hwy
P.O. Box 6100
Hauppauge, NY 11788

Riverhead County Center

County Road 51
Riverhead, NY 11901