July 12, 2023

think tank: geothermal springs, bath houses and mineral pools explained

Written by Grace

It seems as though there are new bath houses and hot springs facilities popping up all over the country right now. This is great news for wellness enthusiasts — or anyone who simply loves immersing themselves in a warm body of water.

Of course, humans have enjoyed balneotherapy (the use of bathing to heal) for thousands of years. Today, more and more of us are awakening to the profound wellbeing benefits offered by this ancient practice.

But what exactly are the distinctions between the various kinds of bathing one can experience?

geothermal mineral springs

Also referred to as ‘true hot springs’, the water in geothermal mineral pools comes from very deep underground. In most cases, geothermal water is the result of a fault in the Earth’s surface, which allows water to travel to the mantle (the area between the Earth’s core and crust), where it is heated and then pushed back towards the Earth’s surface via the faults. If there is a lot of pressure, hot spring water can be seen bursting out of the Earth, which is known as a ‘geyser’.

The water in the hot pools at Peninsula Hot Springs comes from 637 metres underground.

Hot springs pools themselves can occur naturally — for example the thermal pool found at Mataranka in Australia’s Northern Territory. Other times the water is manually brought to the surface and a pool is built to catch the water. Because the water is so hot when it reaches the earth’s surface, it often has to be tempered with cooler mineral water to be suitable for human bathing.

Geothermal mineral water is naturally rich in minerals. The precise mineral composition depends on where in the world the hot spring is situated, and different minerals carry their own health benefits. The mineral water at Peninsula Hot Springs, for example, is full of boron, magnesium, potassium, chloride and bicarbonate, and these minerals have been shown to help with everything from skin, bone and joint health to nervous system regulation.

Some of the most famous geothermal mineral springs can be found in Japan, Iceland, the USA, New Zealand, Turkey, Italy — and, of course, right here on the Mornington Peninsula (thanks to the Selwyn fault line.)

mineral pools

Some spas or bath houses contain pools filled with natural mineral water from an on-site mineral spring, but the water does not come from a geothermal source and is therefore manually heated. Other facilities have manually heated pools and minerals such as magnesium added to the water for their healing benefits.

bath houses

Historically speaking, a ‘bath house’ or ‘bathhouse’ is a built structure containing pools, saunas and other bathing experiences. The term is often interchangeable with ‘public baths’. Traditional Japanese onsen (geothermal mineral pools) and sentō (pools usually filled with regular hot water), Turkish baths (hammam), Korean jjimjilbang and modern facilities containing pools, hot tubs, saunas and spa treatments could all be described as ‘bath houses’.


The word ‘spa’ comes from the Belgian town of the same name, which is known for having mineral-rich therapeutic waters. Historically, a spa is a mineral spring — but over time the word has come to mean both hot tubs and health resorts where people can experience massages and other wellbeing treatments (as in ‘day spa’.)

mud baths

Mud baths sometimes occur naturally in locations where there are geothermal hot springs, and are created by the combination of volcanic ash and geothermal water. People have bathed in warm mud baths for centuries, and many people use mud baths because their rich mineral composition is seen as a boon for skincare and detoxification (among other health benefits.) Mud baths are often recreated in day spa settings.

There are myriad ways to enjoy the health benefits of water — whether you’re looking to be immersed in nature, push yourself to the edges of your comfort zone, heal from injury or simply relax. At Peninsula Hot Springs, we’re delighted to offer a diverse range of globally inspired bathing experiences.

discover our water

"We rejuvenate and renew through relaxation, movement, nutrition, sleep, mindfulness, creativity and being at one with nature" - Charles Davidson

Learn more of the healing benefits of our water

learn more

No recent searches