Lawn Fertilizer (NYS Nutrient Runoff Law) Look for the Zero! Before buying lawn fertilizer, check the bag for a set of three numbers showing the percentage of nitrogen, phosphorus and potassium. Buy a bag with a "0" in the middle. Zero in the middle means phosphorus free and that means…. Zero pollution - Phosphorus is one of the leading causes of water pollution. Even if you live far from a water body, excess phosphorus from your lawn can wash off and pollute lakes and streams, harming fish and ruining boating and swimming. More than 100 water bodies in New York State cannot be used for drinking, fishing or swimming because they contain too much phosphorus.