8/7/2026
KEATONS LAKE HAB UPDATE 8/7/26: Keatons Lake remains CLOSED due to Harmful Algal Bloom (HAB) Conditions.
People and pets should refrain from swimming, kayaking, paddleboarding, or any other activity with a risk of water contact.
Samples collected since the original closure notification have shown PTOX concentrations fluctuating:
Samples collected 07/29/2026 RESULTS: 101,400 Cells/ml.
(showed an increase to an average PTOX algae concentration)
Samples collected 08/04/2026 RESULTS: 42,267 cells/ml.
(showed a decrease to an average PTOX algae concentration)
Lake of the Woods Harmful Algal Bloom Response Protocol sets a lake closure threshold at PTOX values greater than 50,000 cells/ml.
NEXT STEPS:
Treatment Planning: Algaecide treatment has been scheduled for next week Wednesday, August 12, weather permitting. This was the first available date for our treatment providers.
The treatment will use a floating product called Vodaguard. This is essentially the same treatment chemical as has been used previously in Keatons Lake for algae control but is slightly modified to be a floating product. The current potentially toxin producing cyanobacteria affecting Keatons lake are Dolichospermum spp. These cyanobacteria have the capability to be positively buoyant, resulting in them frequently floating near the surface. Using the floating treatment product is expected to result in greater contact time for the treatment, for more effective results over a longer period of time, with less overall treatment product used.
Water Quality Testing: Sampling continues, with the focus on algae cell count data, and toxin data. As conditions change and are monitored the likely path forward is to analyze results as they are received to determine if they support downgrading the lake closure to a swim advisory. From there, repeat testing results being consistently within acceptable thresholds will allow for lifting the advisory and returning to regular lake status.
Continued Monitoring: Water sampling will continue throughout the response process until results indicate it is safe to lift the lake closure or any advisory conditions.
While this event is truly an unfortunate challenge for the community, LOWA staff are using this as an opportunity to learn as much as possible about Keatons Lake and algae bloom management at Lake of the Woods.
To learn more about our testing and what LOWA staff are learning, click HERE.
Keegan Angerer, Environmental Resources Director, shares information on their testing and what they are learning in regards to HAB conditions in Keatons Lake.
Keatons Lake HAB Notice 7/28/26:
Keatons Lake is CLOSED due to Harmful Algal Bloom (HAB) conditions.
People and pets should refrain from swimming, kayaking, paddleboarding, or any other activity with a risk of water contact.
Results from the most recent testing (collected 07/23/2026) indicate that between the three sampling sites in Keatons Lake there is an average of 61,366 cells/ml of potentially toxigenic cyanobacteria (PTOX). Lake of the Woods Harmful Algal Bloom Response Protocol sets a lake closure threshold at PTOX values greater than 50,000 cells/ml.
Recent testing result is a significant jump from our previous results:
07/16/2026-There was an average PTOX concentration of 2613 cells/ml (well below the first threshold of concern in the HAB protocol).
Prior to the 7/16/26 testing Keatons Lake had negligible PTOX levels in the weekly sampling conducted up until 07/16/2026.
Keatons lake will remain closed until further testing results support a change in status.
Actions Currently Underway:
Water Quality Testing: As part of our ongoing monitoring program, water samples were collected today to test for the two algal toxins most commonly associated with the type of cyanobacteria currently present in Keaton's Lake. Barring any unexpected delays, laboratory results are expected by the end of next week (August 8, 2026).
Treatment Planning: LOWA is working with our environmental partners to move forward with treatment as quickly as possible. Preparations are occurring concurrently with testing so that treatment can begin promptly.
Continued Monitoring: Water sampling will continue throughout the response process. Algae cell concentrations and toxin levels will be monitored through follow-up testing until results indicate it is safe to lift the lake closure or any advisory conditions.
We will continue to keep the community informed as we monitor progress and await post-treatment results.
To follow our Beach and Lake Statuses which includes water testing results click HERE.
To Learn More about Harmful Algal Bloom (HAB) and FAQ about HAB explore the Virginia Department of Health (VDH) Swim Healthy, Virginia webpage Click HERE.
To Access the Keatons Lake Harmful Algal Bloom Response Protocol Click HERE