Lava Rock Filtration Explained

We've all heard or seen it before in marketing messaging for bottled water brands: lava rock or volcanic rock filtered water. But what does lava rock filtration mean and why should you care about it? All bottled water has to be purified and filtered, but that process strips out many of the naturally occurring minerals in drinking water that make it taste so good. The unique characteristics of volcanic rock, combined with heavy annual rainfall levels on volcanic islands create a natural water filtration process.

What is Lava Rock

Lava rock or volcanic rock is what liquid hot molten lava becomes when it cools and crystalizes. Volcanos spew out magma from the earth's core and deposit it along the slopes of a volcanic mountain. Technically, volcanic rock is a type of igneous rock called basalt, which can be found in abundance in certain part of the world, especially in the pacific volcanic islands. Basalt rock is just about everywhere on earth, and it is even present on the moon. On earth, it underlies all of the great underwater ocean basins, and it abundant in the ocean floors beneath volcanic islands. The porous nature of Basalt, along with other physical characteristics, makes it ideal for the natural filtration of water. This comes in very handy in Hawaii where there are a lot of volcanoes, rainfall and pristine artesian wells. Because certain islands have active volcanos, there is a constant replenishment of new rock, which add to the natural filter.

How Does Lava Rock Filter water

Imagine a sponge, with its rubbery feel, squishy consistency and its porous make-up. Water can pass through a sponge without much trouble. Now imagine that sponge is hard substance with a crusty out layer with porous skin that is made of hard, lightweight silica and other minerals. Water can still pass through it, but also pass over it. Now imagine that giant rock sponge was once in the form of liquid magma, and was formed by cooling and crystalizing. Lava rock is a common filtration media in aquariums and ponds, where the porous surface of the stones creates greater surface area where the biofilm can accumulate and act as a filter for bacteria. In nature, the force of constant rainfall in places like Hawaii utilize the rocky landscape from lava flows from active volcanos to push water through and over the porous rock. Sediment and bacteria collect in the biofilter on the rocks, and excess water flows and drains into artesian aquifers below. This natural filtration allows for certain minerals like magnesium and calcium stay in the water, which gives it a unique alkaline taste.

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What is Distilled Water Used For?

Distilled water is highly purified water that has had minerals and other unwanted impurities removed from it. There are many reasons why certain minerals would need to be removed from water, and they are mostly related to the intended use of water. Purified drinking water is for safe consumption by humans for hydration purposes, and minerals like magnesium, potassium and calcium are minerals the human body needs. Taking minerals out of water, or distilling it, is for other purposed like cleaning, steaming and other water-using machines. However, for the purposes of drinking water, drinking distilled water habitually is not ideal because the human body needs certain minerals like magnesium and calcium, and water is the best way to get it. On the other hand, water that has had minerals removed from it is ideal for use in household appliances like irons and humidifiers because of mineral deposits that can build up. Industrial uses in laboratories require distilled water for scientific reasons in its use in chemical reactions, which requires a very high grade of distilled water create in specialized processes.

How is Water Distilled?

The process of water distillation involves heating and boiling water, converting the liquid into steam vapor. This steam byproduct is then captured and condensed back into liquid water. This process will remove 99.9% of the unwanted impurities that existed in the water prior, and will leave behind the bacteria, chlorine, fluoride, arsenic, mercury, lead, nitrates, viruses and other pathogens, rust, salt, sulfates, pesticides and other harmful contaminants. Industrial strength boilers are used in the mass production of distilled water for bottling and distribution to consumers.

What is Distilled Water Used For?

Because most of the minerals have been remove from distilled water, it ideal for use in machines and appliances that require cleans moving parts, free of calcium or other mineral deposits and build up. For the the average consumer, this means coffee machines, clothing irons, CPAP machines, humidifiers, nasal rinse and other applications. At the industrial scale, hospitals and laboratories require high grade distilled water for many scientific purposes, including laboratory experiment and as a cleaning supply.

Is Distilled Water Safe for Drinking?

In general, in a pinch, it is safe to drink a glass of distilled water. But we know that the human body required certain minerals like magnesium, calcium and potassium, so drinking distilled water normally, instead of regular purified water, is not recommended. Despite its high quality, whether or not distilled water is safe to drink as a replacement for regular drinking water is not easy to determine. The effects on the human body of drinking distilled water remains an under-researched and frequently debated topic. Essential minerals are removed from the water, leading some experts and dieticians to worry about whether it's dangerous to drink over time.

To learn more about how drinking water high in essential minerals tastes, click here.

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What Are Total Dissolved Solids in Drinking Water?

We all need water to survive, and those of us lucky enough to live in the developed world have many choices when to comes to selecting how we get our drinking water. Some people spend extra money on purified water home delivery services, where the water is delivered in large 5 gallon jugs. Others chose to rely on municipal water supplies and get water straight from the tap, and then use home filtration to mechanically filter out impurities. Either way, we need to make sure the water we drink is from a good source and has been filtered, purified and sanitized for human consumption. So what exactly needs to be filtered out? It depends on the source.

Water coming from the ground well or ground aquifers will have what is referred to as total dissolved solids, or TDS. This refers to dirt, chemicals, bacteria, pathogens and other impurities that are small enough to pass through fine filter membranes and end up in the liquid. This is why it is called dissolved solids. TDS is measured on a part-per-million basis or PPM, and is a standard testing benchmark in water purity measurement. In the United States and Canada, a TDS reading of 500 (500 parts per million, which can also be expressed as 500 milligrams per liter) is the threshold for safe water.

TDS (parts per million)


0 to 300


300 to 600


600 to  900


900 to 1,200


Over 1,200



But dissolved solids can be both organic and inorganic, which creates another layer of detail required to evaluate the quality and safety of drinking water. Groundwater naturally contains higher levels of organic solids including inorganic salts like magnesium, calcium, potassium and sodium, which is generally safe at lower levels. In fact, premium alkaline bottled water, high in pH is generally considered to taste better because of these minerals. Dissolved organic solids, like mineral, can also create ‘hard water’ which can clog up appliances like washing machines, dishwashers, coffee machines and the like. Because hard water from the ground is prevalent in certain parts of the US, water softening services and devices are quite popular. Inorganic matter is a different story. Sulfate, iron, manganese, petroleum, pathogens, and other man-made contaminants create much more danger when to come to drinking water, and contribute to TDS.

Measuring the TDS in drinking water is essential to maintain safe drinking water supplies for the general public. When a water source has a high level of TDS, it is likely that there are some harmful contaminants in the water. TDS is also easy to measure and if something is happening to water, such as pollution, and chances are TDS levels will change, so keeping track of these changes can act as an early warning signal that something wrong is going on with the water. For these reasons, it is important to monitor the TDS levels in public water, so that if they change, action can be taken immediately. If you’re interest in measuring the TDS in your tap water home, you can buy an in inexpensive tool here. For more information about how TDS is measured and how we can all maintain safe water supplies, please visit the Safe Drinking Water Foundation website.

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How do Charcoal Water Filters Work?

Many home water filtration systems feature charcoal-based filters, but have you ever wondered exactly how charcoal is used in a filtration system to filter water? Charcoal is a great natural ingredient for water filters, but the charcoal actually used to filter is called activated charcoal, which is different from the charcoal you use in your backyard bbq. Activated charcoal is generally crush up into small pieces, which allows for more water to pass over the surface area of the charcoal, and expose more water molecules to the pores in the charcoal. Activated charcoal purifies through the process of adsorption (not to be confused with 'absorption'), which is where the charcoal chemically binds impurities in the water to the surface of the charcoal filter particles rather than physically absorbing them. Activated charcoal is an ideal water filter because it removes toxins from the water without stripping the water of salts and other important minerals. These adsorption qualities of activated charcoal is why you hear of people using it to try and clean out their system from toxins and impurities like alcohol, and use it as a hangover treatment. There is no real science that supports this idea.

So, for water filtration, there are three primary processes:

  1. Mechanical filtration – This is the process of forcing water, either through pressure or gravity, through a fine membrane to physically or mechanically remove particles and sediment from your water. Small debris like sand, dust, dirt and other sediments are the first foreign substances that need to be removed from water during the purification process. Some filters will emphasis the size of the holes in their filters and membrane by pointing the size of filtered out material in microns. Generally speaking, a 1 micron filter in quite fine and will remove most if not all particulate, as well as small bacterial particles called cysts like Giardia and Cryptosporidium.
  2. Carbon/charcoal filtration – Most water filter systems use the pores within carbon or charcoal to remove the unpleasant tastes and odors which can be caused by a variety of factors, including chlorine and other chemicals, old underground pipes and unstable levels in water tables and aquifers. This second layer or level of filtration ensures that your water looks and tastes as appealing as it can.
  3. Removal of some minerals, including limescale – Limescale and other minerals can accumulate and is not good for your water using appliances like your coffee maker or dishwasher.

Some of the benefits of charcoal-based filtration:

  1. The good stuff isn't filter out of your water, only the bad stuff that might be lingering in your pipes like copper, mercury and cadmium
  2. Your water will taste better. While important in disinfecting your water, chlorine has no value to your mouth and tongue.
  3. Very inexpensive compared to bottled water
  4. Easy maintenance – by replacing the filter every 12 months, you can help make sure the water you drink from you home system will taste as good as it can.

What is Purified Water?

Before a bottle of water can be marketed and sold as “purified water,” its overall level of purification must meet a certain standard or threshold. In other words, its impurity levels must be reduced to a certain level. Water and its contents are measured in parts-per-million, and the purification standard is 10 parts per million. So, in order to be called 'purified', the impurities in the water need to be at or less than 10 parts per million, which is a very small amount. Many consumers get confused about the differences between purified, distilled, and filtered water as it relates to water that can be purchased in a bottle, so it is important to understand the distinctions. All drinking water is subjected to some form of filtration before distribution, plain tap water included. Tap water is generally filtered with charcoal based filtration systems, and then has chlorine added to it to kill of  any bacteria, pathogens and other stuff you don't want in your water. Then flouride is usually added to protect tooth enamel. Purified water is treated to remove additional substances like pathogens and chemicals. The process of distillation is just one example of an extra step taken for purification.

All commercially available purified water meets significantly higher and stricter EPA purity standards than those applied to standard drinking water, tap water included. Consumers should be aware that because of these strict purification standards, purified water may come from almost any source including tap water, existing tap water aquifers and infrastructure, as well as natural springs. Put plainly, water that is 'purified' has gone through an additional process to remove contaminates and particulates (like pathogens and chemicals) that mechanical filtration may have missed, so it doesn't really matter the source.

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