Lake & Pond News
Forever Chemicals Found in 96% of Tested Florida Waterways — and Nationally, 83% of Lakes and Rivers Are Contaminated
A new report from the Environment America Research & Policy Center, released this week, found PFAS “forever chemicals” in 96% of the 23 Florida waterways tested between 2022 and 2024 — including Tiger Lake near Orlando (used for kayaking and fishing) and the Hillsborough River, which supplies Tampa’s drinking water. Across 1,602 tested waterways nationwide, 83% showed contamination. PFAS have been linked to several cancers, high cholesterol, obesity, and developmental problems, and they accumulate in fish tissue — a particular concern for families who eat what they catch.
For lake and pond owners, the takeaway is to stay informed about what your state agencies are — or are not — testing in your area, and to understand how runoff from lawns, farmland, and industrial sites reaches open water. Read our deep-dive on how nutrient and chemical runoff reaches your lake, and if you’re looking for ways to reduce what enters your water, explore our selection of water treatments for lake and pond owners.
Hydrilla Is Tripling in Size Monthly Inside One of North Carolina’s Largest Lakes
High Rock Lake — North Carolina’s second-largest lake, with 365 miles of shoreline — is in an escalating battle with hydrilla, the invasive Asian aquatic plant widely regarded as the worst of its kind. Confirmed in the lake for at least four years, hydrilla patches have reportedly tripled or quadrupled in area within single months. Dense mats grow from the lakebed to the surface in calm coves, crowding out native habitat, clogging municipal water intakes, stalling boat motors, and creating a safety hazard for swimmers. Officials are deploying aquatic herbicides at boat ramps and have stocked sterile triploid grass carp, but expect a two-to-three-year timeline before the infestation is brought under control.
The broader warning for lake owners everywhere: hydrilla spreads almost entirely through fragments that hitchhike on boats, trailers, live wells, and bait buckets. One trip to a contaminated lake can introduce it to your home water. Understand the biology that makes hydrilla nearly unstoppable by reading our science article on why hydrilla is the ultimate aquatic super-weed, and if you’re managing an infestation, browse our aquatic herbicide options for EPA-registered treatments.
Native Plant Buffers Are Protecting Lake Sunapee From Cyanobacteria Blooms
This summer, volunteers and the Lake Sunapee Protective Association transformed eroded shoreline sections at Georges Mills Town Beach and Little Lake Sunapee, planting nearly 400 native shrubs and perennials with support from a $50,000 NH LAKES grant. The new buffers filter stormwater runoff before it reaches the water, intercepting excess nutrients—the fuel that powers harmful cyanobacteria (blue-green algae) blooms. The project is one of six statewide sharing $400,000 in funding through the American Rescue Plan Act, all aimed at keeping phosphorus and sediment out of New Hampshire’s lakes.
Watershed director Geoffrey Lizotte noted that without intervention, eroded shorelines deliver a steady stream of sediment and phosphorus capable of triggering toxic blooms that close beaches, sicken pets, and erode property values. Our science guide on how native plants protect your water quality explains why a planted buffer is your lake’s first line of defense. When blooms do appear, algae control products can help manage the problem before it gets out of hand.
Those “Weeds” You Want Gone May Be Your Lake’s Best Defense
A report from NPR’s All Things Considered—drawing on research from the Minnesota DNR and the University of Florida’s Center for Aquatic and Invasive Plants—makes a counterintuitive case: the native aquatic plants many lake owners wage war on are actually protecting their water. Their roots anchor sediment so it doesn’t cloud the lake, and they absorb excess nitrogen and phosphorus from lawn and farm runoff before those nutrients can spark an algae bloom. Minnesota’s Nisswa Lake, home to more than two dozen native plant species, ranks among the state’s clearest. Remove those plants, scientists say, and nutrient levels climb, algae follows, and shoreline erosion accelerates.
The real target, researchers say, is invasive species—not native plants. Eurasian watermilfoil and curly-leaf pondweed lack the natural enemies that keep native plants in balance, allowing them to crowd out everything else. Scientists also raised a caution: some chemical treatments for aquatic plants contain PFAS compounds that break down slowly in aquatic environments. Our science overview on aquatic weeds and lake health helps you tell native from invasive, and our aquatic weed control options focus on targeted approaches that manage problem species while leaving your lake’s native ecosystem intact.
DNR to Property Owners: Inspect Your Dock and Gear for Invasive Species Before Winter Storage
The Iowa Department of Natural Resources is urging lake property owners statewide to inspect boats, docks, boat lifts, and trailers for aquatic invasive species before pulling equipment for the winter. With fall storage season underway, wildlife biologists warn that zebra mussels and Eurasian watermilfoil can hitch a ride on gear now and end up infesting a new water body come spring.
Aquatic vegetation management biologist Jason Euchner advises running your hand over smooth dock surfaces — juvenile zebra mussels are often felt before they can be seen. The Clean, Drain, Dry protocol takes only minutes: remove all visible plants and animals, drain every drop of water from live wells and hulls, and let everything dry at least five days before launching on another lake. For a deeper look at how invasive plants and animals spread and what to watch for on your own property, see our guide to aquatic invasive species. If milfoil or other invasive weeds have already taken hold in your water, our aquatic herbicides can help you treat them before the new season begins.
Lake Erie Alert: Toxic Algal Bloom Lingers in Western Waters into October
A harmful cyanobacteria bloom continues to affect western Lake Erie this week, with NOAA and Cooperative Institute for Great Lakes Research scientists tracking low-to-medium concentrations stretching from near Monroe, Michigan, toward Leamington, Ontario. Patches are also reported near the Michigan and Ohio shorelines, including Maumee Bay near Toledo.
Researchers caution that even where open-water toxin levels appear low, surface scums can concentrate cyanotoxins to dangerous levels — so visible scum or foam anywhere on the water should be treated as a hazard. Keep pets and children away from discolored water or any surface accumulation and check NOAA's latest HAB forecast before heading out. Understanding what drives bloom formation is the first step in protecting your own waterfront; our harmful algal bloom science overview covers the key risk factors every lake owner should know. For those managing algae on a private pond or smaller lake, our algae control products include EPA-registered copper-based and natural treatments sized for a range of water bodies.
Pyramid Lake Still Under Cyanobacteria Advisory — A Reminder That Fall Blooms Are Real
Nevada's Pyramid Lake remains under an active health and safety advisory this week as cyanobacteria abundance increased along multiple shorelines, according to the Pyramid Lake Paiute Tribe Water Quality Program. The largest buildup is near Dago Bay on the south end, where tribal Natural Resource employees observed strong odors, abundant algae growth, and harm to fish and wildlife. Residents and visitors are advised to avoid all direct contact with bloom material and to bring their own drinking water to the lake.
Late-season blooms catch many lake and pond owners off guard. Warm water temperatures can linger well into October, and fall rains often deliver a fresh pulse of phosphorus and nitrogen into lakes just as summer recreation tapers off — creating ideal conditions for cyanobacteria to surge. Our article on managing pond algae through the seasons explains the year-round bloom cycle and what triggers late-fall flare-ups. One of the most effective long-term prevention strategies is bottom aeration — browse our full lineup of pond aerators to keep water circulating and oxygen levels high heading into next spring.
Toxic Algae Hits Snake River for the Fourth Straight Year
Harmful algal blooms have returned to the Snake River for the fourth consecutive year, with Whitman County Public Health issuing fresh warnings for a roughly 50-mile stretch between Blyton Landing and Little Goose Dam. Water samples collected in August tested positive for microcystin — a liver-damaging toxin that cannot be neutralized by boiling. The algae may appear as blue-green patches resembling spilled paint, or show up as brown, red, or pink discoloration.
Health authorities urge everyone — people, pets, and livestock — to stay out of any discolored water. Experts point to dams as a key factor: slower currents create the warm, nutrient-rich conditions that cyanobacteria thrive in. Before 2023, toxic algae had never been documented in this river system. If your own lake or pond is heading into fall with reduced water movement, our article on how to respond to a harmful algal bloom emergency is essential reading — and browsing our algae control products now, before you need them, is even better.
Two Tiny Invaders Threatening New Hampshire’s 1,000 Lakes and Ponds
New Hampshire’s roughly 1,000 lakes and ponds are on alert for two small but disruptive invaders: Chinese mystery snails and spiny water fleas. Chinese mystery snails — capable of producing up to 170 offspring in a lifetime and surviving out of water for several days — have likely been present in the state since 1980 and are steadily outcompeting native snail populations. Spiny water fleas, tiny crustaceans now confirmed in lakes Winnipesaukee, Newfound, and Winnisquam, disrupt the food chain by consuming the organisms that small fish depend on for nutrition.
Unlike many invasives, neither species can be effectively removed once established — making prevention everything. NH Lakes runs a voluntary boat inspection program at about 100 ramps annually and has intercepted more than 1,500 invasive fragments over 25 years by teaching boaters to clean, drain, and dry their gear before every launch. Our guide to evaluating your lake’s aquatic management program walks you through what to monitor season by season, and our aquatic weed control products help you stay a step ahead of whatever your water sends your way.
Citizen Scientists Are Using DNA Traces to Catch Zebra Mussels Before They Spread
University of Minnesota researchers are enlisting citizen volunteers to fight invasive zebra mussels using environmental DNA — a technique that detects an invasive species from the genetic residue it sheds into the water, before a single shell is visible to the naked eye. This summer, volunteers collected water samples from 52 Minnesota lakes using simple test kits. Results are expected within two to three months and will give lake managers an early warning window to act before populations spiral out of control.
Zebra mussels typically go unnoticed until infestations are already severe, but eDNA testing could change that. The Minnesota Aquatic Invasive Species Center plans to expand the program to other invasive species and eventually offer fee-based testing services to lake associations and local governments. Want to sharpen your own monitoring instincts? Our guide to identifying a healthy northern lake covers the seasonal signs to watch for — and if zebra mussels have already triggered secondary plant growth on your water, our aquatic herbicides can help you reclaim your shoreline.
Starry Stonewort and Zebra Mussels Confirmed in Two Minnesota Lakes
The Minnesota Department of Natural Resources confirmed two of the most destructive aquatic invasive species in Cass County last week — starry stonewort in Six Mile Lake and zebra mussels in both Six Mile Lake and Little Wolf Lake. The algae-like starry stonewort has now invaded 40 Minnesota waterbodies since it was first detected in the state in 2015. Officials note a sobering fact: starry stonewort has never been eradicated from any U.S. lake or river. It spreads through dense mats that crowd out native aquatic plants and degrade habitat, and it hitches rides on boats, trailers, and fishing equipment that haven't been properly cleaned.
Prevention is the only real defense — knowing how to identify submerged aquatic weeds and invasive species before they gain a foothold is the first line of protection for any lake property owner. Where established infestations do take hold, targeted aquatic herbicides remain among the most effective management tools available for slowing spread and protecting your shoreline.
Arkansas Lake Hit With Harmful Algal Bloom Advisory — Cyanobacteria Confirmed
Arkansas environmental officials issued a harmful algal bloom advisory for Mom's Lake in Corning (Clay County) this week after state inspectors visually confirmed the presence of cyanobacteria. The public is urged to avoid all contact with the water, with heightened warnings for children, pets, and livestock. Cyanobacteria toxins can cause headaches, muscle spasms, shortness of breath, and gastrointestinal illness in people — and can be fatal to dogs within hours of ingestion. Officials advise washing any animal that contacts the water immediately with clean tap water and contacting a veterinarian right away if symptoms appear.
This advisory is far from an isolated event: algal bloom warnings have spread across California, Utah, the Midwest, and the South this season, making 2026 one of the most active HAB years in recent memory. Understanding how phosphorus fuels algae and what binding treatments can do is essential for any lake or pond owner who wants to get ahead of this problem — and pairing that knowledge with proven algae control treatments gives you a real defense before blooms take over.
Algal Blooms Don't Stop When Summer Does — Utah Has 27 Active Advisories Heading Into Fall
Utah state officials are reminding fall recreationists and waterfowl hunters this week that harmful algal blooms don't end with summer. As of September 22, 27 water bodies across Utah carry active watch or warning advisories — including Deer Creek Reservoir and Echo Reservoir, which are under warning-level status. State monitoring officially closes October 31, but blooms can persist well into cold weather. Officials urge anyone heading onto the water this fall to learn to identify the signs: pea-green or blue-green coloring, surface scums, foam, or water that looks like spilled paint. Hunters are specifically warned to clean harvested waterfowl thoroughly and discard guts and skin.
For pond and lake owners, this is a critical reminder that fall is actually one of the best windows to act. Aeration keeps water moving and oxygen-rich — conditions that make it much harder for cyanobacteria to bloom. Read how surface aeration can disrupt existing algae blooms and reduce next season's risk, then browse our selection of pond aerators designed to keep your water healthy through fall and into the off-season.
North Dakota’s Harmful Algal Bloom Count Reaches 20 Waterbodies
North Dakota’s Department of Environmental Quality added three more lakes and reservoirs to its harmful algal bloom advisory list this week — Blacktail Dam, Horsehead Lake, and Larimore Dam — bringing the statewide total to 20 active waterbodies under warning or advisory status. Warm, sunny late-summer and early-fall conditions are the main driver, and officials say blooms can develop with little warning. Six of those 20 sites carry the more serious “Warning” designation, meaning toxin levels are high enough to pose significant health risks to people and animals.
People and pets should avoid swimming in, drinking from, or playing near water that appears green, blue-green, or scummy — and remember that boiling water does not destroy cyanotoxins, it can concentrate them. If you want to understand what drives these late-season outbreaks, our science team explains why cold-water lakes still get algae blooms in fall — and if your pond has a history of summer or fall blooms, browse our algae control products for treatments you can apply now before conditions worsen heading into October.
Minnesota’s “Lake Killer” Starry Stonewort Now in 40 Waterbodies — and Researchers Still Have No Long-Term Fix
Eleven years after starry stonewort was first detected in Minnesota, the invasive algae has now colonized 40 lakes and reservoirs statewide — and researchers have yet to find a permanent solution. The species forms dense, fast-growing mats that crowd out native aquatic plants, tangle boat motors, and make swimming areas unusable. Because it reproduces through tiny star-shaped bulbils buried in lake sediment, even aggressive chemical and mechanical treatments suppress it rather than eliminate it. Lake Koronis alone spends roughly $170,000 a year in ongoing management just to hold the infestation in check.
Early detection is still the most effective tool lake owners have: a small infestation is far easier — and far cheaper — to contain than an established one. Our guide to mechanical vs. chemical vs. biological weed control walks through what each approach can and can’t do, so you’re prepared if invasives show up on your water. And if you already have an infestation, browse our aquatic herbicides for EPA-registered options suited to invasive aquatic vegetation.
Florida Health Officials Issue Water Quality Advisory After Bacteria Spike at Alligator Point
The Florida Department of Health in Franklin County issued a recreational water quality advisory on September 18 after tests at Alligator Point confirmed elevated levels of Enterococcus bacteria. The bacteria, which come from the intestinal tracts of humans and animals, can cause skin rashes, eye irritation, and gastrointestinal illness when swimmers are exposed. Officials warned against any water-related activities at the location until bacterial counts return to safe levels. Late-summer heat, wildlife activity, and agricultural or stormwater runoff are common triggers for these late-season spikes.
Pond and lake owners should note that enclosed or slow-moving water is especially prone to bacterial buildup when nutrient levels are high — the same conditions that feed algae. Understanding how nutrient loading drives water quality problems is a good starting point for any property owner managing a private pond. Keeping water circulating and treated is one of the best defenses going into fall — browse our water treatment products to find bacteria, enzyme, and clarifier options suited to your pond size.
North Dakota Expands Harmful Algal Bloom Watch List to 11 Waterbodies as Late-Summer Blooms Surge
North Dakota’s Department of Environmental Quality added four more lakes and reservoirs to its harmful algal bloom list this week, including Buffalo Lodge Lake and Lake Darling — both elevated to full “warning” status, meaning toxin levels have exceeded safe recreational thresholds. Epping-Springbrook Dam and Blacktail Dam in Williams County carry advisory status, indicating active blooms without yet reaching dangerous concentrations. The state now tracks 11 waterbodies under active HAB alerts, a pattern consistent with the record-setting summer heat of 2026 that has kept water temperatures elevated well past the typical peak bloom window.
Late-season heat sustains cyanobacteria growth deep into September and even October, so now is not the time to let your guard down. Check your state health department’s HAB map before swimming or letting pets near the water, and consider whether surface aeration can disrupt algae mat formation on your own water body. For active or recurring blooms, targeted algae control treatments can reduce cyanobacteria populations before conditions turn dangerous.
California Issues Highest-Level Danger Advisory at Lake Pillsbury as Microcystin Levels Nearly Double the Safe Threshold
California’s State Water Resources Control Board issued its most severe tier of toxic algae advisory for Lake Pillsbury in Mendocino National Forest after water samples returned 23.84 micrograms per liter of microcystins and nodularins — nearly double the state’s 20-microgram danger threshold. Lake County Health Services is urging all residents and visitors to keep people and pets entirely out of the water until further notice. The warning extends well beyond Pillsbury: the North Coast Regional Water Quality Control Board has confirmed toxic algal mats in the Navarro River near Hendy Woods State Park and the East Fork Russian River, while nearby Clear Lake carries multiple active danger and caution designations across its monitoring network.
Microcystins are liver-damaging toxins that neither boiling nor standard filtration can neutralize — and they can persist in water long after the visible bloom has faded. If your pond or lake shows green or blue-green discoloration, surface foam, or a paint-like sheen, treat it as a potential HAB before anyone goes near the water. Our breakdown of algaecides vs. herbicides explains exactly which product category to reach for when you’re dealing with a true algae event. Pairing that treatment with ongoing beneficial water treatments can restore balance and reduce the nutrient load that fuels future blooms.
Michigan Lake Association Deploys Full-Shoreline Herbicide Treatment to Stop Invasive Eurasian Milfoil From Spreading
The Crockery Lake Association in Michigan partnered with Professional Lake Management to treat the lake’s entire shoreline for invasive Eurasian watermilfoil discovered at multiple sites around the lake. The herbicide application, completed September 10, was specifically formulated to penetrate root systems and prevent the plant from regrowing next season. Association leaders issued a pointed warning to lakefront residents: do not hand-pull floating milfoil. Every fragment left in the water can root in a new location, turning a localized problem into a lake-wide infestation. Early-fall timing was deliberate — plants are still actively transporting nutrients into their roots, helping herbicide move deep into the system for maximum effect.
Eurasian watermilfoil is one of the most destructive aquatic invaders in North America, forming dense surface mats that shade out native plants, tangle propellers, and ruin swimming areas. It spreads almost entirely through plant fragments hitching rides on boats, trailers, and fishing gear — making clean-drain-dry protocols at every launch critical. If you’re seeing an aggressive weed surge on your lake or pond, our step-by-step guide to safe and effective aquatic herbicide application walks you through the process from identification to treatment. Browse our full line of EPA-registered aquatic herbicides to find the right formula for your specific weed species and water conditions.
Harmful Algal Blooms Are Closing Lakes Across the Country Right Now
Multiple lakes shut down swimming this past week as harmful algal blooms (HABs) hit states from California to Michigan to Arkansas in the same seven-day window. Lake Hemet and Big Bear Lake in Southern California, Lake Cadillac and Austin Lake in Michigan, and Lake Poinsett in Arkansas all received official advisories — every one of them triggered by cyanobacteria, the toxic blue-green algae that thrives in warm, nutrient-rich late-summer water.
Cyanotoxins can cause rashes, vomiting, and neurological symptoms in people — and can be fatal to dogs within hours of exposure. If your water looks green, cloudy, or has a musty smell, keep everyone out until you know it's clear. Our guide to telling harmful blooms from harmless green algae walks through exactly what to look for — and browse our algae control products if you're ready to take action before next season.
Your State Just Stopped Watching Your Lake. The Algae Didn't Get the Memo.
Indiana's Department of Environmental Management wrapped up its 2026 official recreational lake sampling season this week — with nine lake sites still under advisory as of its final report. That's standard practice in most states: sampling programs close down right around Labor Day whether or not conditions have improved, and no new official alerts will be issued after that, even if blooms intensify into September or October.
Here's the problem: late summer into early fall is actually one of the riskiest windows for cyanobacteria. Warm water that hasn't turned over yet, concentrated nutrients from a season of runoff, and calmer winds all create perfect bloom conditions — right when the state stops watching. Knowing what to look for yourself matters more than ever after Labor Day. Understanding why your lake turns green is the first step — and if you're looking for a long-term solution, aeration systems are one of the most effective ways to prevent bloom conditions from forming in the first place.
This Invasive Weed Doubled in One Season. Now Idaho's Lake Is Calling In Herbicides.
Payette Lake in McCall, Idaho reached a critical tipping point this week: a Eurasian watermilfoil infestation more than doubled in a single growing season — from roughly 149 tons in 2025 to 320 tons in 2026. The Idaho State Department of Agriculture scheduled the lake's first-ever herbicide treatment for September 11th, applying ProcellaCOR across 43 acres. ProcellaCOR mimics a plant growth hormone that causes milfoil to essentially grow itself to death, with minimal impact on native species at labeled rates.
This is a story every lake owner should pay close attention to. Eurasian watermilfoil spreads through fragmentation — a single piece on a boat trailer or kayak paddle can seed an entirely new infestation. Left untreated, it can double its coverage in one season, exactly as it did at Payette. Learn how to identify and control watermilfoil before it reaches that point — and if you're already seeing it, browse our aquatic herbicides to understand your treatment options for this season and next.