Potomac River, United States
There are various reasons not to take a dip in the Potomac River — not least that swimming in certain sections is illegal under US law and likely to land you in trouble with the authorities here.
The legalities aside, swimming just isn’t safe here. With the hazards ranging from white water rapids to deadly bacteria and overflowing sewage pipes, our recommendation would be to seek somewhere else to practice your strokes.
It can be tempting to take the chance in Maryland’s Great Falls area — aka Mather Gorge — but don’t be fooled by the beautiful surroundings.
This is a dangerous spot, with strong currents, deep waters and hidden hazards that result in frequent drownings. Closer to Washington DC, high E.coli readings continue to cause concerns, whilst flash floods often result in sewage being dumped into the river. One to avoid? For sure.