Lake Erie Western Basin harmful algal bloom homeowner playbook

Microcystin is a potent liver toxin produced by cyanobacteria (blue-green algae), specifically Microcystis. It is heat-stable, meaning boiling water does not destroy it. Ingestion can cause nausea, vomiting, and long-term liver damage, while skin contact often results in rashes, hives, or blisters.

From August 2–4, 2014, a 'Do Not Drink' advisory was issued for over 400,000 residents after microcystin levels in treated city water reached 1.6 ppb, exceeding safety limits. The event was triggered by a massive bloom pushed by strong winds directly over the city’s water intake in the Western Basin.

The NOAA Lake Erie HAB Forecast provides satellite-based tracking and 5-day trajectory outlooks. During the peak season (July–October), comprehensive analysis bulletins are issued every Monday and Thursday to help residents anticipate when blooms may approach their shoreline.

Residents can report suspected algal blooms or water quality concerns directly to the Ohio EPA HAB hotline at 1-800-644-3044. You can also email photos and locations of suspected blooms to HABmailbox@epa.ohio.gov.

Standard residential UV systems and basic cartridge filters are generally NOT effective at removing microcystin. While specialized high-intensity UV can degrade the toxin, homeowners should rely on a combination of activated carbon (GAC) and reverse osmosis (RO) systems, and must have their treated water professionally tested during active blooms.

Dock-water refers to raw lake water pumped directly for irrigation or cleaning; it is untreated and highly dangerous during a bloom. City water is treated at municipal plants (like Toledo or Sandusky) which use advanced ozone or carbon treatment to neutralize toxins before it reaches your tap.

It is safe when there are no active 'Public Health Advisories' or 'Algal Bloom' warnings posted on the Ohio BeachGuard system. Visually, avoid any water that looks like spilled green paint, has a 'pea soup' appearance, or shows floating scum/mats.

Children and pets have lower body weights, making even small amounts of toxin more dangerous. Dogs are especially at risk because they often lick algae off their fur or drink directly from the shoreline where toxins concentrate in the highest densities.

The primary cause is excessive phosphorus and nitrogen runoff, largely from agricultural fertilizers in the Maumee River watershed. Warm water temperatures and calm winds in late summer allow these nutrients to fuel rapid cyanobacteria growth.

The official bulletins are hosted by the NOAA National Centers for Coastal Ocean Science (NCCOS). They provide seasonal severity projections in June and twice-weekly updates throughout the summer and fall.