Lawn Fertilizer Initiative

Completed in 2014


In appropriate concentrations, nitrogen in the form of oxides plays a critical role in the nitrogen cycle and is essential to life. In excess, these forms of nitrogen represent an environmental pollutant that has the potential to harm our water resources, and ultimately damage human health. Excessive amounts of nitrogen, as well as phosphorus, contribute to undesirable algal and aquatic plant growth, and degrade the water used for drinking and shellfishing as well as swimming and boating. 

Groundwater is also at risk from nitrogen infiltration. Rising nitrogen levels in our Island ponds are caused in major part by rising nitrogen content in our groundwater. The groundwater/aquifer underlying Tisbury is the source of its existing and future drinking water supply and should be preserved and protected from excess nitrate infiltration. Ingested nitrates are converted by the body into nitrites, which are capable of converting hemoglobin into an oxidized form that does not bind tightly to blood oxygen. Infants, young children, pregnant women and some people with compromised immune systems who drink water in excess of established Safe Drinking Water Standards are particularly vulnerable and may become seriously ill if untreated. The Island’s municipal and well water supply is an outstanding asset, one that is safe now and should be protected going forward.

This Regulation provides for a reduction of nitrogen and phosphorus going into the Island’s Water Resources by means of an organized system of education, licensure, regulation of practice, and enforcement. The Regulation is intended to contribute to the island’s ability to protect, maintain, and ultimately improve the water quality in all its Water Resources and assist in achieving compliance with any applicable water quality standards relating to controllable nitrogen and phosphorus.