Portland, Oregon (CNN) Elevated levels of caffeine have been found in the water off the Oregon coast.
You might be thinking it's because of the thousands of coffee shops in the Pacific Northwest, but that may not be the case.
Researchers from Portland State University and Washington State University, Vancouver say they found the higher levels in areas not near heavily populated areas or potential pollution sources, like water treatment plants.
The caffeine appears to come from sewers and septic tanks.
These findings indicate that treatment plants are effective at removing caffeine from the water, and septic tanks, which are used at state parks, might not be doing a good enough job of containing pollutants.
Caffeine is usually a marker of wastewater contaminants, so researchers say there may be other pollutants in the waters that have a human source.
The caffeine amounts are well below a lethal dose for marine life.