With the excessively high temperatures and dry weather patterns, creeks are drying up and flow from springs is low. These conditions increase the likelihood of toxic algae mats in creeks and lakes. The most recent lab results, from testing in May and June, have confirmed the presence of toxic algae at several locations, including Barton Springs. 

Analysis by Austin Water showed no concerning levels of toxins in the water at Barton Springs Pool, and the pool remains open. The City monitors the water quality of Barton Springs and will continue to do so. 

While the presence of toxic algae does not necessarily mean toxins in the water, it is still important to take precautions. Never drink water directly from lakes, creeks or springs, avoid contact with algae and rinse off after contact with the water. Do not allow pets to drink from these waterways and do not allow dogs to lick their fur prior to rinsing if they’ve been in the water.  

Bacteria, such as E. coli, parasites and other dangers may also be present in natural waterways. Do not swim in water if it is warm, stagnant or if you see scum, film or algae. Due to the risk of bacteria, you should also avoid natural water bodies for at least three days after it rains or if a lot of dogs are present.    

Health and Reporting Guidelines:  
The City of Austin has received no reports of human or animal illness from any of the sampling sites. More information on symptoms is available from the Centers for Disease Control and Prevention: https://www.cdc.gov/habs/illness-symptoms-freshwater.html.  

If a person has sudden, unexplained symptoms after swimming, they should contact their medical provider or the Texas Poison Control Center at 1-800-222-1222. For pets, contact a veterinarian. Please also let us know by completing the reporting form, found at AustinTexas.gov/Algae. 

Ongoing Algae Monitoring and Mitigation Efforts:  
The City’s routine algae monitoring program includes biweekly visits to six sites on Lady Bird Lake and Lake Austin during the summer and early fall. If blue-green algae are present at a site, staff take samples of algae and water and sends them to a lab for analysis. The testing and monitoring provide a snapshot of conditions at specific locations at the time samples were taken. This is the most current data available to evaluate the extent of harmful algae but is not suitable for determining the safety of a particular area on a particular day for recreational use.   

In addition to routine monitoring, the City is in the third year of a pilot program to mitigate harmful algae in two areas of Lady Bird Lake. The program consists of applying lanthanum-modified clay which binds to phosphorus, a key source of nutrients for algae. Once bound into a mineral form, the phosphorus becomes unavailable and may help prevent the growth of harmful algae. More information about this program is available here.  

The City of Austin and the U.S. Geological Survey is currently partnering in a scientific study of local springs to further understand the distribution of potentially toxic blue-green algae mats around Austin and the environmental conditions associated with their presence. The study includes looking at a wide range of water quality indicators near several Austin springs over the course of the summer and fall. The City is making the algae toxin data publicly available while the study is underway.  

Lab Results:
The results from the May and June sampling revealed various toxins at several sites. Dihydroanatoxin, homoanatoxin, anatoxin, saxitoxin, cylindrospermopsin and microcystin were all detected in at least one algae sample.  

The sites with toxic algae include:  

Regular Monitoring 

• Red Bud Isle on Lady Bird Lake  
• Vic Mathias Shores on Lady Bird Lake  
• Festival Boat Ramp on Lady Bird Lake  
• Jessica Hollis Park on Lake Austin  

Scientific Study of Springs 

• Barton Springs Pool  
• Backdoor Spring on Barton Creek  
• Bluff Spring on Onion Creek  
• Harris Spring on a tributary to Onion Creek  
• Kizer Spring on Williamson Creek  
• Cold Spring on Lady Bird Lake