This Natural Swimming Hole Stays at a Cool 68°F All Year While Austin Sizzles in the Heat

Barton Springs, Austin

Ask any Austinite where to find 68-degree salvation in the Texas heat, and they’ll point you to Barton Springs. This three-acre pool, fed by underground springs pumping out 800,000 gallons a day, has been keeping Austin weird and cool since way before anyone made bumper stickers about it. Here are some interesting facts about it.

Was Almost Sold for Bourbon

In 1918, Andrew Zilker sold the land with Barton Springs to Austin for $100,000 but nearly took an offer from a Kentucky bourbon maker first.

The whiskey firm tried to convince Zilker again in 1925 but were blocked by a city rule. At one point, they sent Zilker rare bourbon as gifts to sway him.

Zilker’s 2020-discovered diary reveals he preferred the bourbon plan but felt pressured by the townspeople. The bourbon firm later bought land ten miles south.

The Science Makes It Cooler

The springs keep a pH of 7.2 all on their own. One kind of pool moss can’t live if the pH goes past 7.4, so it acts as a live test. Another found the pH has not moved more than 0.3 in fifty years of tests.

Folks from wetland groups come each year to learn how this works. The same kind of rock that helps the pH here was used to help fix a sick lake in western Texas.

Health Boost from Minerals

The pool has a mix of good-for-you bits like small trace forms of stuff that helps your mood and fight swells.

The spring’s base rock adds a type of zinc most pools don’t have. The chill of the pool helps your blood move well.

Tests found the mix is richest just at dawn when few have used the pool yet. One test found that the pool helps your skin’s top layer make new cells.

It Used to Help People Find Dates

In the 1950s, Barton Springs had a dating tradition. If a woman could stay in the cold 68°F water for 15 minutes, she was a match. Old logs show men took up to eight dates there before finding their love.

The test came back in style in 2020. Local bars will ask you, “Have you done the Springs test?” as a chat line, and the pool gift shop sells “I Passed the Test” shirts.

Five past town chiefs have had their first dates at the pool.

The Underwater Forest Look

On spring mornings, light hits the pool just right, making the algae-lined bottom look like a forest below, best near the diving board.

The first known note of this look was in a worn 1887 trip log found at the state house. Each year, the “forest floor” moves a bit as pool flow shifts sand bars.

The city now keeps some areas of algae growth on purpose. When storms come, the view is wild, with the “trees” swaying in the flow bursts.

The Old Guard Tree Legend

A huge old tree near the low end was set to be cut down in 2021, but scans found its roots stop pool mud from washing out.

Marks on its trunk show old pool depths from past droughts. The bark was used as food by native tribes who write about the tree guarded the spring.

New tests show it may be much older than we first thought, well past 300 years. Today, a small plaque by the tree tells how it was saved from the ax.

The Sunken Book Box

In 1981, books about Texas land were sealed in a clear, dry box and sunk near the dive board as an art piece.

Crafted by the same man behind the Frost Bank Tower, the box’s lid is made from old pool rock, and a small “in case” piece floats up as a leak indicator.

The books swap out twice a year, and you can vote on what fills the box next. One book includes a map tracing the spring’s underground path.

A guest book lets you jot down which titles you read while wet.

Secret Films Shot Here

The pool has shown up in big films, like “The Tree of Life” and “Underwater.”

Crews like how the clear blue water looks on film, and the rock walls add depth. At least eight TV shows have used it as well, and two known ad spots.

The pool was used for five days of the new James Bond film, with some night shots. For one shoot, they had to drain half the pool.

Visiting Barton Springs Pool (2025 Info)

Where: 2201 Barton Springs Road, Austin, TX 78746

When:

• 5:00 AM to 10:00 PM each day
• Closed for clean-up on Thursdays from 9:00 AM to 7:00 PM

Cost:

• Austin locals: $5 for grown folks, $3 for kids/old folks
• From out of town: $9 for grown folks, $5 for kids/old folks
• Free to swim before 8:00 AM and after 9:00 PM

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