Maryland Fertilizer Law

Nutrients—primarily nitrogen and phosphorus—are key ingredients in lawn fertilizer. When it rains, excess nutrients can wash off the land and into the streams and rivers that feed the Chesapeake Bay. Once in our waterways, excess fertilizers contribute to the growth of algae blooms that block sunlight from reaching Bay grasses, rob the water of oxygen and threaten underwater life.

Montgomery County does not directly regulate fertilizer usage, but the County abides by the rules set by state law.

Be Wise: Don't Over-Fertilize

The Maryland Fertilizer Law limits the amount of nutrients that can be applied to lawns or turf and restricts phosphorus content in lawn fertilizer. The goal is to help homeowners and lawn care professionals maintain healthy lawns without applying unnecessary amounts of nitrogen and phosphorus.

What You Can Do:

If possible, wash your vehicle at a commercial carwash facility, where the wash water is treated before getting into our local waterways. Commercial businesses that wash vehicles, including portable vehicle-detailing operations, are prohibited from discharging wash water to the environment. The businesses are required to direct all wash water to the sanitary sewer which goes to the local wastewater treatment plant or capture and contain it to be hauled off-site for proper disposal.

Consider washing your vehicle on a porous surface, such as a lawn, where the wash water can soak into the soil, be treated by soil particles and microbes, and be filtered before it enters the groundwater.

  • Read and Follow all label instructions

  • Do not fertilize if heavy rain is expected

  • Keep fertilizer away from streams, sidewalks and driveways

  • Don't fertilize between November 15 and March 1

  • Hire only certified professionals to fertilize lawns

Homeowners and do-it-yourselfers are required to follow University of Maryland recommendations when fertilizing lawns. Mandatory restrictions, similar to those imposed for lawn care professionals, apply