Question 1

What is Distilled Water?

Accepted Answer

Distilled water is water that has been purified by turning it into steam by boiling and then condensing it back into a liquid. This simple but effective process removes almost all dissolved minerals, salts, metals and many other impurities. The result is an ultra pure, consistent form of water that behaves in a predictable way in many applications.  Although distilled water looks the same as tap water in a glass, it is very different on a microscopic level. Ordinary tap water contains dissolved minerals such as calcium and magnesium, as well as traces of metals, chlorine, organic matter and other substances from pipes and treatment systems. Distilled water has had almost all of these removed.    How Distilled Water Is Made    The process used to produce distilled water is called distillation. It works by using the natural water cycle as a model: evaporation, condensation and collection.  Water is first heated in a stainless steel vessel until it begins boils. As it boils, water molecules leave the surface of the liquid as steam. Most dissolved solids and many contaminants do not turn into vapour at this stage. They are left behind in the boiling chamber.  The steam is then directed into a separate, cooler chamber via a reflux condensing column. Here it passes through coils or a condenser where it loses heat. As it cools, the steam turns back into liquid water. This liquid is now highly purified because the majority of non-volatile impurities were left behind.  The condensed water is collected in a clean container as distilled water. In industrial and laboratory settings, the equipment is designed to ensure that the steam does not pick up contaminants from the air or from the surface of the condenser. In many systems, the water may be distilled more than once to achieve even higher levels of purity.    Distilled Water and Other Types of Water    It is helpful to understand how distilled water compares with other common types of water.  Tap water is treated to be safe to drink. It usually contains chlorine or chloramine to control bacteria, as well as dissolved minerals picked up from reservoirs and pipes. It is suitable for general household use, but its composition varies from place to place.  Spring water and mineral water are taken from natural sources. They contain high levels of minerals such as calcium, magnesium and bicarbonates. These minerals can give water a pleasant taste but also leave scale in kettles and appliances.  Filtered water has passed through a basic filter to remove certain contaminants. Depending on the filter, this may reduce chlorine, some metals, or particles. However, most dissolved solids and microbes remain.  Deionised water is treated using ion-exchange resins to remove charged particles, such as mineral ions. It can be very pure, but will still contain organic compounds, bacteria, or other non-ionic contaminants.  Distilled water has been purified by phase change, from liquid to vapour and back again. This allows it to remove both dissolved solids and many other impurities. It is widely used where predictable, low-mineral water is essential.    Why Purity Matters    The very low mineral content of distilled water makes it useful in settings where ordinary water could cause problems.  Mineral deposits are a common issue with tap water. When water containing calcium and magnesium is heated, it leaves limescale behind. Over time this can coat heating elements, pipes and jets. It reduces efficiency and can cause equipment to fail. Distilled water greatly reduces this build-up.  Electrical conductivity is another important factor. Dissolved salts allow water to conduct electricity. In sensitive electronic equipment, even a small amount of conductivity can be problematic. Because it has very low levels of dissolved ions, distilled water is much less conductive than tap water.  Consistency is also valuable. The composition of tap water changes with the source, the season and the treatment process. Distilled water is produced in a controlled way, so each batch should meet the same standard. This is important for laboratories, manufacturing, medical devices and many technical processes.    Common Uses of Distilled Water    Distilled water is used in many settings where purity and consistency are important.  In laboratories, it is used to prepare solutions, clean equipment and feed instruments. Impurities in water can interfere with chemical reactions, affect measurements and damage delicate components.  In medical and dental environments, distilled water is used in autoclaves, sterilisers and some patient equipment. This helps protect instruments from scale and supports reliable sterilisation cycles.  In industry, distilled water can be used in cooling systems, battery top-ups, steam irons, humidifiers and cleaning processes. Using distilled water reduces scale and residue, which can improve performance and extend the life of equipment.  In the home, many people use distilled water in steam irons, garment steamers, CPAP machines, facial steamers, aquariums (when mixed and balanced correctly) and for cleaning items such as camera sensors or glass surfaces where streaks and spots are not acceptable.    How Quality Is Measured    The quality of distilled water is often assessed using measures such as conductivity and total dissolved solids (TDS). These give an indication of how many ions or particles remain in the water after distillation.  Low conductivity and low TDS values suggest that very few dissolved substances are present. In many technical applications, specifications will state maximum acceptable levels for these measures. For example, laboratory-grade distilled water is held to stricter limits than water used in general industrial settings.  Microbiological quality can also be important. Although the distillation process reduces many microorganisms, storage conditions matter. Containers and handling equipment should be clean and suitable for contact with pure water. For this reason, distilled water for critical applications is produced, stored and transported under controlled conditions.    Storing and Handling Distilled Water    Distilled water is more 'active' in some ways than ordinary water because it has so few dissolved substances. Over time, it can slowly dissolve small amounts of materials from the surfaces it touches. This is one reason it is usually stored in suitable plastic or glass containers that are designed for pure water.  Containers should be kept sealed when not in use. This helps prevent dust, airborne particles and gases from dissolving back into the water. For example, carbon dioxide from the air can gradually increase the conductivity of distilled water.  It is good practice to store distilled water away from direct sunlight and sources of heat. This helps maintain its quality and reduces the risk of microbial growth in long-term storage. For sensitive applications, many users prefer to open smaller containers as needed, rather than a single large container that is repeatedly opened and closed.  By understanding what distilled water is, how it is produced and where its purity matters most, it becomes clear why it is chosen for so many technical, medical, industrial and household tasks where ordinary tap water is not ideal.

Question 2

How is Distilled Water different from Deionised Water?

Accepted Answer

How Is Distilled Water Different from Deionised Water?    Distilled water and deionised water are both forms of purified water, but they are not the same. They are made in different ways, they remove different types of impurities, and they are suited to different uses. Understanding these differences helps you choose the right water for your equipment, processes and day-to-day tasks.  At a glance, both types of water look identical. The real difference lies in what has been removed, what may still remain, and how predictable the water is in demanding environments such as laboratories, industry and medical settings.    What Is Distilled Water?    Distilled water is produced using heat. The process of distillation relies on changing water from liquid to vapour and back again.  Water is heated until it boils and turns into steam. Most dissolved solids, such as mineral salts and most metals, do not boil at this temperature. They are left behind in the boiling chamber as the steam rises. The steam is then cooled in a separate section of the equipment, where it condenses back into liquid water. This condensed liquid is collected as distilled water.  Because many impurities are left behind during boiling, distilled water is very low in dissolved minerals (TDS). It also removes a good proportion of many heavy metals and some microorganisms. The result is a clean, consistent and predictable water quality.  In some cases, water is distilled more than once  (such as our triple distilled water)  to achieve even higher levels of purity. It is used where extremely low levels of contamination are essential.    What Is Deionised Water?    Deionised water, sometimes written as de-ionised water or DI water, is produced using a much cheaper method. Instead of boiling, deionisation uses resins to remove charged particles from the water.  These resins are usually contained in columns or cartridges. As water passes through them, dissolved ions in the water are exchanged for hydrogen and hydroxide ions on the resin. The hydrogen and hydroxide then combine to form pure water, while the unwanted ions are held on the resin.  Deionisation is very effective at removing dissolved mineral ions, such as calcium, magnesium, sodium and chloride. As a result, deionised water can have very low conductivity and can be extremely low in total dissolved solids, especially when produced by high-quality systems and maintained correctly.  However, deionisation only targets  charged  particles. It is less effective at removing uncharged organic molecules, bacteria, viruses and dissolved gases. For this reason, deionised water may still contain substances that are not removed by the ion-exchange process.    The Key Differences in Purity    Distillation and deionisation both aim to purify water, but they focus on different groups of contaminants.  Distilled water is purified by vapourisation and condensation. This step removes most dissolved minerals and many non-volatile contaminants. It can also significantly reduce microorganisms.  Deionised water is purified by ion-exchange. This method is excellent at removing ions, which are charged particles. It can produce water with extremely low conductivity, which is useful in electrical and electronic applications. Nevertheless, deionisation does not specifically remove uncharged organic compounds or microorganisms.  In practice, distilled water tends to offer broader removal of many different kinds of impurities. Deionised water can reach very low ion levels, but its overall purity depends on the quality of upstream and downstream treatment.    How They Are Used in Practice    The choice between distilled and deionised water is often based on the level of purity required and cost-effectiveness.  Distilled water is commonly used where a consistent, low-mineral water is needed and where the presence of organic residues or microorganisms must be reduced. Typical uses include:  Autoclaves and sterilisers, Medical and dental equipment, Laboratory reagents and washing, Steam irons and garment steamers, CPAP machines and humidifiers, Lead-acid batteries and some cooling systems  Deionised water is often used where large volumes of purified water are needed without the energy cost of boiling. Common uses include:  Electronics manufacturing and circuit board rinsing, Industrial processes that require very low ion content, Some laboratory instruments and analytical systems, Automotive cooling and rinsing tasks, Mixing with additives where ionic contamination must be minimised  In some high-end systems, water may be both distilled and deionised, or treated with a combination of technologies, to meet very strict purity requirements.    Which Is Better: Distilled or Deionised?    There is no single answer that fits every situation. Instead, each type of water has its strengths.   Distilled water is generally preferred when:   You want a broad reduction in many types of contaminants. You need water that has been physically separated from its original impurities by vapourisation. You are using devices, such as autoclaves or steam-based equipment, that specify distilled water.   Deionised water is generally preferred when:   Low electrical conductivity is critical. You need large volumes of cheaper purified water on demand, often on-site. Your process already includes additional purification stages that complement deionisation.  For many everyday uses, such as topping up batteries, feeding steam irons or supplying humidifiers, either high-quality distilled water or high-quality deionised water may be acceptable, provided they meet the equipment manufacturer’s recommendations. For more sensitive applications, the specification of the device or process should always be followed carefully.  Both distilled and deionised water require suitable storage and handling to maintain their quality. Because they are low in dissolved minerals, they can slowly dissolve small amounts of material from containers, pipes and fittings. For this reason, they are usually stored in suitable plastic or glass vessels designed for purified water.  Containers should be kept closed when not in use to reduce contamination from dust, particles and gases in the air. Over time, contact with the atmosphere can increase the conductivity of purified water as it absorbs carbon dioxide and other substances.  From a safety perspective, both distilled and deionised water are simply purified forms of water. They are not inherently dangerous in normal use. However, they can behave differently from tap water in certain technical contexts, especially where electrical conductivity, corrosion or microbiological control are important.  Understanding how distilled water differs from deionised water, and how each one is produced, makes it easier to select the most appropriate type of purified water for your specific application, whether that is in a laboratory, an industrial setting, a medical environment or around the home.

Question 3

How should distilled water be stored?

Accepted Answer

Distilled water is water that has been purified by boiling and condensing the steam, which removes minerals and most impurities. Distilled water is commonly used for appliances, laboratory work, car batteries, steam irons, humidifiers, aquariums, and some medical devices such as CPAP machines. Because it is very low in dissolved minerals, it is often chosen when people want consistent water quality and reduced limescale. Correct storage matters because distilled water can very easily pick up contaminants after it has been produced, and it can take on tastes and odours from its surroundings if it is not handled well.  Storing distilled water is not complicated, but it does require attention to the container, cleanliness, temperature, light exposure, and how often the container is opened. The goal is to keep the water as close as possible to its original purity until the moment it is used.    Choose the right container    The container is the most important storage decision because distilled water can absorb trace substances from surfaces over time. A suitable container should be clean, food-safe, and made from a material that does not easily transfer flavours, odours, or chemicals into the water.  High-quality plastic containers such as our food-grade HDPE bottles and drums are widely used for distilled water because they are lightweight and resistant to shattering.  Glass is an excellent option for smaller quantities because it is generally non-reactive and does not hold odours. Amber or dark glass can be helpful if the water will be exposed to light, although a cupboard is usually enough. Glass is heavier and breakable, so it is best when the container will not be moved frequently.  Stainless steel containers can be suitable, particularly for short-term storage and transport, but they should be designed for storing water and should be thoroughly cleaned. Containers made for other purposes may have seams, linings, or internal finishes that are not ideal for maintaining purity. Aluminium containers are not recommended because they can react with water in certain conditions and are more likely to affect taste.    Keep the lid sealed and minimise opening    Distilled water stays cleanest when it remains sealed. Each time a container is opened, airborne particles and microbes can enter, and the inner surfaces can be touched accidentally. Repeated opening also increases the chance of introducing contamination from funnels, scoops, or bottles that are not fully clean.  If you need to use distilled water regularly, it is often better to store it in multiple smaller containers rather than one large container that is opened daily. This approach reduces exposure and helps preserve the quality of the unopened portions. It also reduces the chance that a single contamination event affects your entire supply.  Caps should be screwed on firmly and stored upright. An upright position reduces the contact area between water and the cap, which is helpful because caps can hold odours or residues more easily than the main bottle.    Store in a cool, stable location    Temperature affects both the container and the water’s tendency to pick up odours. Distilled water should be kept in a cool, dry place where temperatures do not swing dramatically. A cupboard, pantry, or utility room shelf is usually suitable. A stable indoor environment is generally better than a garage or shed, where temperatures can vary and where the air may contain fuels, solvents, paints, or other chemicals that could be absorbed as odours.  Avoid storing distilled water next to radiators, boilers, hot pipes, tumble dryers, or direct heat sources.    Protect it from sunlight and strong smells    Direct sunlight is not ideal for stored water. Light exposure can warm the container and may encourage algae growth if any contamination occurs, especially in clear containers. Distilled water itself does not contain nutrients that support growth, but contamination can introduce them. Storing bottles in a dark cupboard or opaque storage box is a straightforward way to reduce this risk.  Distilled water can also absorb odours from the environment, particularly when stored in plastic. Keep it away from petrol, diesel, paint, varnish, cleaning chemicals, scented detergents, air fresheners, and anything with a strong smell. Even if the lid is closed, odours can linger around caps and external surfaces, and plastic can take on smells that later transfer to the water when poured.    Keep containers and tools clean    Cleanliness is essential when refilling or decanting distilled water. If you pour water into smaller bottles, use containers that have been washed thoroughly and rinsed well. Any soap residue can affect the taste and may interfere with certain applications, such as laboratory work, humidifiers, and steam irons.  Use a clean funnel and allow it to dry completely before use. Damp funnels stored in cupboards can collect dust and microbes. If you use a jug to measure, keep it dedicated to water and do not use it for other liquids. Cross-contamination is one of the most common ways distilled water loses its purity at home.  Do not dip hands, cloths, or unclean utensils into stored water. Pouring is better than scooping, and a tap dispenser that is designed for water storage can be helpful if it is kept clean and used correctly.    Understand shelf life and practical timeframes    Distilled water does not spoil in the way that milk or juice spoils, but it can become less suitable for certain uses if it is contaminated or if it absorbs odours and trace substances such as carbon dioxide from the atmosphere. Shelf life is therefore less about the water 'going off' and more about how well the water’s original purity is preserved.  If distilled water is factory-sealed and stored in a cool, dark place, it can remain suitable for a long time - up to 12 months. Once opened, the practical storage time depends on how it is handled. Water that is opened frequently or decanted with non-sterile equipment should be used sooner. Water that is opened occasionally, poured carefully, and resealed promptly will generally remain suitable for longer.  For sensitive applications, such as laboratory work, medical devices, or situations where mineral-free water quality is critical, it is sensible to use distilled water relatively soon after opening and to avoid topping up old containers with new water. For less sensitive uses, such as topping up a steam iron, the water can remain usable for a longer period provided it remains clean and odour-free.    Watch for signs that storage has gone wrong    Stored distilled water should look clear and should not have floating particles, cloudiness, or a noticeable odour. If you see sediment, slime, or discolouration, the water has likely been contaminated or the container has degraded. If the water smells of plastic, chemicals, or a musty cupboard, it may still work for some non-critical uses, but it is not ideal and should not be used where purity is important.  Also inspect the container itself. If a plastic bottle becomes soft, warped, cracked, or develops a persistent smell, replace it. If the cap seal looks damaged, do not rely on it for long-term storage.    Special considerations for common uses    Distilled water is often stored near the item it will be used with, but location can be a problem. For example, a garage shelf might be convenient for car batteries, but garages commonly contain fumes and chemicals. In that scenario, a sealed container stored indoors is usually a better choice, with only a small working bottle taken to the garage when needed.  For humidifiers and CPAP-type devices, contamination control matters because water can sit warm in reservoirs, which encourages microbial growth. Storing distilled water carefully reduces what enters the device, but the device reservoir still needs routine cleaning and drying. Only pour what you need, keep the main bottle sealed, and avoid letting the water bottle mouth touch the device opening.  For steam irons, distilled water should be kept away from fragranced laundry products and cleaning sprays stored in utility rooms. A dedicated cupboard shelf and a clean pouring funnel reduce the chance of introducing residues that may later spray or stain fabrics.    Best practice checklist for storage    A good routine is straightforward. You should store distilled water in a clean, food-safe container with a tight cap. You should keep it upright, sealed, cool, and out of sunlight. You should keep it away from strong smells and chemicals. You should pour rather than scoop, and you should use clean, dry tools if you decant into smaller bottles. You should use smaller containers if you open them frequently. You should discard water that becomes cloudy, develops particles, or takes on an unusual smell.

Question 4

Does distillation remove heavy metals?

Accepted Answer

Yes, distillation effectively removes heavy metals from water. 
 During our distillation process: 
 
 
 Water is boiled, converting it to steam. 
 
 
 The steam rises, leaving heavier contaminants, including heavy metals like lead, arsenic, mercury, cadmium, and copper, behind. 
 
 
 The steam then condenses back into purified water in a separate container. 
 
 
 Distillation is highly effective in producing water virtually free of heavy metals.

Question 5

What is the pH of distilled water?

Accepted Answer

Pure distilled water typically has a neutral pH of around  7.0  when produced. 
 However, once exposed to air, distilled water quickly absorbs carbon dioxide (CO₂), forming carbonic acid. This slightly lowers the pH, typically to around  6.5 , making distilled water  very  mildly acidic when tested after being stored or exposed to air. 
 Airtight containers minimise exposure to carbon dioxide and airborne contaminants, reducing acidity changes and microbial growth. We always recommend replacing the lid soon after use.

Question 6

Is Distilled Water the best water to use in a CPAP machine?

Accepted Answer

Distilled water is the best choice for CPAP machines. Distilled Water: 
 1.  Prevents Mineral Build-up  
 
 
 Distillation removes nearly all minerals, preventing mineral deposits (limescale) from building up inside the humidifier tank. 
 
 
 Mineral deposits can damage your CPAP machine over time and will require more frequent cleaning. 
 
 
 2.  Reduces Risk of Bacterial Growth  
 
 
 Distilled water has minimal impurities, reducing the likelihood of bacterial or microbial growth in your humidifier chamber. 
 
 
 3.  Extends the Lifespan of Your CPAP Equipment  
 
 
 Using distilled water prevents damage from contaminants and minerals, extending the lifespan of your humidifier chamber, hoses, and seals. 
 
 
 4.  Improves Breathing Comfort  
 
 
 Distilled water ensures clean, contaminant-free moisture, reducing the chance of respiratory irritation caused by impurities or allergens found in tap or bottled water. 
 
 
 5.  Simplifies Maintenance  
 
 
 Easier cleaning and maintenance since there's less mineral residue or microbial growth.

Quantity	Unit discount	You Save
5	£0.50	£2.50
10	£1.00	£10.00
20	£1.50	£30.00

5 Litre Distilled Water

Pure, Distilled Water - Now Available in 5 Litre Containers

Uses & applications