Swimming in streams, ponds and waterfalls: leptospirosis

Hawaiʻi's freshwater streams, ponds and waterfall pools can carry leptospirosis, a bacteria spread by animal urine. The state Health Department advises not swimming or wading in them, especially with cuts, and not putting your head under.

• You can get it by swimming or wading in fresh water, or touching wet soil or plants contaminated by animal urine.
• Risk is higher with open cuts or sores, and if your head goes under (eyes, nose, mouth).
• Do not drink stream or pond water unless it has been boiled or treated.
• Illness can start 2 days to 4 weeks after exposure, with fever, headache, chills and muscle aches.
• If you get sick after freshwater exposure, see a doctor and mention it. It is treated with antibiotics.
• Ocean water is not the concern here; this is about fresh water.

Source: Hawaiʻi Department of Health: Leptospirosis

Last checked Oct. 29, 2026. Hours, fees and rules can change, so confirm with the official source before you go.