Harmful Algal Bloom in Smith Mountain Lake Prompts Swimming Advisory

If you are in areas along the Blackwater River arm of Smith Mountain Lake in Bedford, Franklin and Pittsylvania counties, a harmful algal bloom (HAB) means you should stay out of the water. The water in coves and creeks may look a bright teal color in these areas and may have a scum on the surface that is bluish, white or bright green.  

The harmful algae in this part of the lake can make you sick if you swallow it or have it on your skin. Symptoms can include skin rash, upset stomach, nausea, vomiting and diarrhea. Small children and pets who are more likely to drink lake water, should be kept away from this area of the lake. 

Algal blooms can happen when warm water, lots of sunlight, and nutrients combine. Visual signs of a bloom can disappear and reappear throughout the day. Most algae are harmless, but some can produce toxins. Algae and cyanobacteria are both important for a balanced environment.

An advisory is posted warning people to avoid activities such as swimming, windsurfing, stand-up-paddle-boarding or any other activity that could cause people to touch or swallow the water. Boating and fishing may continue if boaters take care to avoid contact with the water. 

To see a map of the area of the lake under advisory, visit the VDH interactive Harmful Algal Bloom map.  Expand the map, click on the points around the lake for more information and enter your location in the search bar if you would like to see where you are located on the map compared to the area of the advisory.

The Virginia Department of Health (VDH) and the Virginia Harmful Algal Bloom Task Force, which includes VDH, the Virginia Department of Environmental Quality, and the Old Dominion University Phytoplankton Laboratory, is monitoring the water quality in the lake.

Advisories will be lifted once two tests, taken 10 days apart, show levels of harmful bacteria, or toxins, have dropped to safe levels.

It’s best to keep children and pets from drinking from natural bodies of water. If you or your pets have been in water with a harmful algal bloom, here are some tips to avoid getting sick:  

  • Quickly wash off children and pets with plenty of fresh, clean water after contact with algal scum or water that has blooms.
  • Seek medical/veterinarian care if you or your animals have symptoms after swimming in or near an algal bloom.
  • Properly clean fish by removing the skin and discarding all the internal organs.
  • Cook fish to the proper temperature to make fish fillets are safe to eat.
  • Contact the Harmful Algal Bloom Hotline at 1-888-238-6154 if you suspect you got sick from contact with water that had a harmful algal bloom.
  • Visit www.SwimHealthyVA.com to learn more about harmful algal blooms or to report an algal bloom or fish kill.


You can read more about the advisory on the Smith Mountain Lake – Blackwater River HAB Status Report June 6, 2023. For more information on healthy and safe swimming, visit the VDH Swim Healthy, Virginia page.