Flood waters that took lives and destroyed homes throughout the Hill Country over the long July Fourth weekend, also saturated the Central Texas region, pushing contamination and debris through creeks and waterways. While the storms' full environmental impacts may take weeks to assess, Austin-area officials warn they could be serious.
"It's really important to emphasize that stormwater runoff, even from smaller rain events, washes high levels of bacteria and other pollutants into creeks," Austin Watershed Protection's Ryan Hebrink said. "Best safety practice [is] to stay out of water for several days after rainfall."
Hebrink, whose team oversees environmental spill response, said Austin was fortunate that flooding was not as bad within city limits as in other parts of the region.
"We have not seen a spike in spills or other reports. I think a lot of folks were probably hunkered down during the wet weather over the weekend," he said.
Hebrink said he expects he may get more reports of spills this week if people see more damage as they are out and about.
The city of Austin has closed Bull Creek, Barton Creek and areas of the Colorado River from the Tom Miller Dam to below the Longhorn Dam, including Lady Bird Lake for "personal and commercial" watercraft until Tuesday afternoon. The ban includes creeks and streams.
Mosquitos are about to get really bad
Heavy rains mean lots of standing water and that provides ideal conditions for a mosquito population boom.
"This massive rainfall will raise the risk of mosquito-borne diseases in our community," Marcel Elizondo, Austin Public Health's environmental health services division chief, said in a statement.
Mosquito bites can be more than just an annoyance. According to preliminary data, 33 cases of West Nile virus, including two deaths, were reported in Travis County in 2024.
Austin Public Health is encouraging people to empty standing water in their yards and neighborhoods to prevent the spread of "infections such as Zika, West Nile, dengue fever, encephalitis and canine heartworm."
The city has more tips on how to protect yourself on its website. You can learn more here.
There are no big risks to drinking water right now
Some neighborhoods in Georgetown were put under a boil water notice on Saturday after a water main break "likely related to the flooding conditions in the area," according to a city Facebook post.
In Austin, the city's water utility said it anticipates no risk to its water treatment and distribution operations.
In 2018, river flooding upstream of the city brought so much runoff into Austin's water treatment system that it lead to a city-wide boil water notice.
But, this time, upstream flood gates have remained largely closed, gathering water in depleted reservoirs. That means churned up, runoff-rich flood waters have not been as big a problem for the utility.
"Unlike the 2018 flood event when floodwaters were released downstream, the floodgates at Lake Travis remained closed during the recent weather event. This retention of water is expected to promote settling and help mitigate turbidity concerns," Charles Celauro, Austin Water's assistant director of engineering services, said.
Austin Water said it has also improved its treatment processes to help "efficiently remove suspended solids in water," since the 2018 event.
The reservoirs that supply Austin are refilling
At the start of this spring, the reservoirs of Lake Travis and Lake Buchanan, the main water suppliers for Austin and many downstream customers sat around half empty, triggering enhanced drought restrictions from the Lower Colorado River Authority, the group that manages water from the Highland Lakes.
Those reservoirs are now more than 70% full and rising due in large part to the historical rainfall.
According to the LCRA, Lake Travis rose by 20 feet between July 3 and the afternoon of July 7 and could rise and additional foot or two over the next several days.
"This is still a dynamic situation and the projections could change if we receive additional rain," LCRA Public Information Officer Clara Tuma told KUT in an email.
That replenishment of the reservoirs will relieve some short-term water scarcity concerns for the region, but all that water rushing into the system also poses some of the same health and safety risks detailed earlier in this report.
"LCRA is strongly encouraging everyone to stay off lakes Buchanan, Inks, LBJ, Marble Falls and Travis for the next several days because of fast flows, flood debris and the potential to come in contact with bacteria," wrote Tuma. "We will post on social media and LCRA.org when the advisory is lifted."
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