If you live near a lake, river, or stream, there’s a good chance your town or state has rules about what kind of fertilizer you can use. Over the past two decades, dozens of states and hundreds of counties and municipalities across the U.S. have enacted laws restricting phosphorus in lawn fertilizers. These rules exist for good reason: excess phosphorus is one of the biggest culprits in water pollution, driving algae blooms, harming fish, and even threatening drinking water supplies.
The good news? With Lawnbright, staying compliant — and protecting your waterways — is simple. All of our lawn care plans are designed with low or no phosphorus, so you can keep your lawn healthy without worrying about fines or runoff.
Why Phosphorus Is a Problem Near Waterways
Grass actually doesn’t need much phosphorus once it’s established. But when fertilizer with phosphorus is spread on a lawn near a shoreline or driveway, rain can easily wash it into nearby streams or lakes. In water, phosphorus acts like a supercharged growth booster for algae. A single pound of phosphorus can fuel up to 500 pounds of algae growth. That algae starves the water of oxygen, creates “dead zones” where fish can’t survive, and sometimes produces toxins harmful to pets and people.
It only takes a small amount to cause a big problem — aquatic systems need 1,000 times less phosphorus than terrestrial plants. That’s why more and more communities are saying “enough is enough.”
Where Fertilizer Restrictions Exist Today
Minnesota was the pioneer. Shorewood passed the first local ordinance back in 1985, limiting fertilizer to 3% phosphorus or less. By 2005, the state banned phosphorus fertilizer use statewide unless a soil test shows a deficiency. That law worked — phosphorus in lawn fertilizers dropped by nearly half within just a few years, and most products on the shelves are now phosphorus-free.
Other states quickly followed. Today, at least 11 states — including New York, New Jersey, Vermont, Virginia, Michigan, Maryland, and Washington — limit phosphorus in most lawn fertilizers near waterways.
In Florida, counties have taken things even further.
-
Seminole County prohibits phosphorus entirely unless a soil test proves it’s needed. From June through September, residents can’t apply any fertilizer with nitrogen or phosphorus at all, in order to protect waterways during the rainy season.
-
Pinellas County enforces similar “blackout periods,” plus a year-round phosphorus restriction.
-
Miami-Dade County bans phosphorus year-round and requires at least a 20-foot buffer from water bodies.
New England has also joined in:
-
Connecticut restricts fertilizer use within 20 feet of water (15 feet if using a precision spreader).
-
New Hampshire prohibits fertilizer within 25 feet of water, and between 25–50 feet of a water source - and this can include a storm drain - only allows low-phosphorus products.
Out west, Washington State has rules protecting Lake Whatcom, and in the Chesapeake Bay region, both Maryland and Virginia tightened fertilizer laws to reduce runoff into the Bay.
What to Look for in Lawn Fertilizer
If you live near water — or just want to do the right thing — here’s what matters most:
-
Check for phosphorus on the label. Fertilizer bags list N-P-K (nitrogen, phosphorus, potassium). Look for a middle number of 0 (or very low, ≤3%).
-
Follow buffer rules. Even low-P fertilizer shouldn’t be applied right up to the water’s edge. Most ordinances require a 10- to 25-foot buffer.
-
Use soil testing. Some states only allow phosphorus if a recent soil test shows your lawn actually needs it.
-
Choose slow-release nitrogen. Many ordinances (like Miami-Dade’s) also require fertilizer with at least 65% slow-release nitrogen to reduce runoff.
-
Mind the seasons. Blackout periods (like Florida’s summer bans) mean you can’t apply at certain times of year.
Why Lawnbright Is the Easy Choice
Sorting through all these rules can feel overwhelming, but Lawnbright makes it simple. Every Lawnbright plan is formulated with low or no phosphorus and slow-release nitrogen — meaning our products already meet or exceed most local restrictions.
Even better, our plans are customized for your region and your soil, so you’re not just compliant — you’re actually giving your lawn exactly what it needs. We also send timely reminders so you apply at the right time, steering clear of blackout periods and maximizing results.
And because Lawnbright products are non-toxic and family-friendly, you’re not just protecting your waterways — you’re creating a safer lawn for kids, pets, and neighbors.
The Bottom Line
Phosphorus restrictions aren’t going away — in fact, they’re spreading as more communities work to protect water quality. Instead of trying to keep track of dozens of local ordinances, you can trust that Lawnbright has already done the homework for you.
With Lawnbright’s low-phosphorus lawn care plans, you’ll:
-
Stay compliant with state and local rules
-
Protect your local lakes, rivers, and streams
-
Enjoy a healthy lawn that’s safe for your family
Ready to simplify your lawn care and safeguard your waterways? Explore Lawnbright’s Low-Phosphorus Plans today.
Frequently Asked Questions About Low-Phosphorus Fertilizer Rules
Q: Why are states banning phosphorus in lawn fertilizer?
A: Excess phosphorus is one of the leading causes of water pollution in lakes, rivers, and streams. It fuels harmful algae blooms, depletes oxygen for fish, and can even contaminate drinking water. Most established lawns already have enough phosphorus, so limiting fertilizer use has big environmental benefits without harming your grass.
Q: Does my lawn actually need phosphorus?
A: Not usually. Unless you’re starting a brand-new lawn from seed or sod, soil typically has enough phosphorus. Soil tests are the best way to know for sure — and in many states, a soil test is required before you can apply phosphorus legally.
Q: Which states have phosphorus fertilizer restrictions?
A: States including Minnesota, New York, New Jersey, Vermont, Virginia, Michigan, Maryland, Maine, Illinois, and Washington have statewide restrictions. Florida has extensive county-level ordinances, and New England states like Maine, Connecticut and New Hampshire have shoreline buffer rules. Many other counties and municipalities also enforce local bans.
Q: How can I tell if a fertilizer contains phosphorus?
A: Check the N-P-K numbers on the fertilizer label. The middle number represents phosphorus (P). For example, a fertilizer labeled 20-0-10 has no phosphorus, while 15-5-10 contains 5% phosphorus.
Q: What are fertilizer blackout periods?
A: Blackout periods are times of year when applying certain fertilizers is prohibited — usually during rainy seasons when runoff risk is highest. For example, many Florida counties ban nitrogen and phosphorus fertilizer use from June 1 through September 30.
Q: How does Lawnbright make this easier?
A: Lawnbright plans are already low-phosphorus (often zero) and customized for your soil and region. That means you don’t need to worry about breaking local rules — plus, our reminders and product timing keep you aligned with blackout periods automatically.