National Park Service LogoU.S. Department of the InteriorNational Park ServiceNational Park Service
National Park Service:  U.S. Department of the InteriorNational Park Service Arrowhead
Hot Springs National Parkcampsite with bright blue dome tent on right, red pickup truck on pad on left; several rvs in background
view map
text size:largestlargernormal
printer friendly
Hot Springs National Park
Frequently Asked Questions--The Hot Spring Water

1)  What makes the water hot?
Water that falls as rain in the recharge or watershed area sinks about a mile deep through faults and fractures. As it goes deep into the earth, it becomes heated by the natural heat gradient of the earth and compression. The hot water then rises quickly through a fault at the base of Hot Springs Mountain.

2)  Where's the recharge area for the hot springs?
The recharge area or watershed for the hot springs is the area to the northeast and east of the park, including Hot Springs Mountain, North Mountain and Indian Mountain.

3)  What's in the hot spring water?

Silica (SiO2)  

53.0

Bicarbonate (HCO3)

130.0

Calcium (Ca)

47.0

Sulfate (SO4)

7.8

Magnesium (Mg)

4.9

Sodium (Na)

4.0

Chloride (Cl)

2.2

Fluoride (F)

0.26

Potassium (K)

1.4

Oxygen (O2)

4.5

Free Carbon Dioxide (CO2)

9.7

Radon gas emanation amounts to 43.3 picocuries per liter. This low level of radioactivity is well within safety limits. Exposure to air allows further dissipation of the gas.

4)  How hot is the water?
The average temperature for the hot spring water emerging is 143º F or 62º C.

5)  How much hot spring water emerges each day?
Approximately 700,000 gallons are collected each day in the hot spring water reservoir.

6)  Where do the hot springs emerge?
The hot springs only emerge at the base of Hot Springs Mountain on the western slope. They emerge through a fault and do not occur any where else in the park except in the downtown Hot Springs part of the park.

black and white photo of Rector's bathhouse, a small one story frame building near the edge of Hot Springs Creek  

Did You Know?
In May 1862, Arkansas Governor Henry Massie Rector moved the state government to his hotel and bathhouse located on Hot Springs Reservation, now Hot Springs National Park. That July, the government seat was moved further south to Old Washington for the remainder of the Civil War.

Last Updated: August 18, 2006 at 09:55 EST