Recreation
Carbon monoxide
The odorless, colorless gas in boat exhaust that accumulates behind the transom and poses a serious poisoning and drowning risk to riders close to the boat.
Carbon monoxide is a term from limnology — the scientific study of inland waters. The detailed explanation below covers the definition, why the concept matters to lake water-quality interpretation, and how it intersects with the LakeGrade rubric. Reading Carbon monoxide alongside the LakeGrade rubric helps make the rubric's structure intuitive — each grading parameter maps directly onto an established limnological concept.
The per-lake pages on LakeQuality always show the specific Carbon monoxide value for that lake, so you can move from the general concept to the specific lake without leaving the site.
What It Means for Your Lake
Carbon monoxide (CO) is a poisonous, odorless, colorless gas in the exhaust of gasoline engines. Behind a moving boat the airflow forms a low-pressure burble where CO accumulates in a pocket, exactly where a wakesurfer's head sits when riding close to the transom. Symptoms, nausea, dizziness, headache, confusion, fainting, are easily mistaken for sun, motion, or exhaustion, and victims can be overcome within minutes and drown. The deadliest version is teak surfing, dragging behind the swim platform. To reduce risk, riders should stay out of the exhaust stream, never linger in the water close behind a running boat, and many use fresh-air-exhaust systems that route fumes into the prop wash and away from the rider.
Frequently Asked Questions
What is carbon monoxide?
The odorless, colorless gas in boat exhaust that accumulates behind the transom and poses a serious poisoning and drowning risk to riders close to the boat.
Why does carbon monoxide matter for lake health?
Carbon monoxide (CO) is a poisonous, odorless, colorless gas in the exhaust of gasoline engines. Behind a moving boat the airflow forms a low-pressure burble where CO accumulates in a pocket, exactly where a wakesurfer's head sits when riding close to the transom. Symptoms, nausea, dizziness, headac...
Related Terms
An exhaust system that injects engine fumes into the propeller wash and underwater, dramatically lowering carbon monoxide around the rider.
The dangerous, often illegal practice of holding onto a boat's swim platform to bodysurf the wake, exposing the rider directly to lethal carbon monoxide.
The area of water immediately behind the boat near the propeller where a fallen rider is at greatest risk, prompting an immediate engine shutdown.
The turbulent low-pressure pocket of air directly behind a moving boat's transom where exhaust and carbon monoxide collect.
Source: EPA National Aquatic Resource Surveys, 2026.