Demineralised water is ordinary water that has had almost all of its dissolved minerals removed. It is sometimes called de-ionised or demin water. It looks the same as tap water, but that missing mineral content makes it the right choice for a surprising number of jobs in workshops, fleets and industry. It is also the base ingredient we use to make AdBlue®.
Why remove the minerals?
Tap water carries dissolved salts such as calcium, magnesium, sodium and chlorides, and the amount varies from town to town. For drinking, that is fine. For many technical jobs it causes problems:
- Scale — minerals deposit on hot surfaces, blocking passages and reducing heat transfer.
- Corrosion — some dissolved salts speed up corrosion of metals.
- Spotting — when water evaporates from a surface, minerals are left behind as marks.
- Contamination — in batteries, chemical mixes and processes, minerals can react or interfere.
Demineralised water avoids these issues because there is very little in it to leave behind.
Common uses
Battery top-up
Flooded lead-acid batteries in trucks, forklifts, machinery and standby power systems lose water over time and need topping up. Using tap water adds minerals that can build up and shorten battery life. Demineralised water is the standard choice. Always follow the battery maker's instructions on levels and safety.
Cooling system top-up
Many coolant concentrates are designed to be mixed with demineralised water, and it is commonly used for top-ups too. Minerals in hard water can form scale in radiators and engine passages. Check the coolant manufacturer's recommendations for the right mix.
Spot-free washing and rinsing
A final rinse with demineralised water leaves glass, paintwork and polished surfaces without water spots. Detailers, truck washes and equipment cleaners use it for exactly this reason.
Industrial and process uses
Demineralised water is widely used in industry, including:
- Steam boilers and humidifiers, where scale is a constant concern.
- Mixing cleaning chemicals and concentrates to a consistent strength.
- Laboratories, and rinsing equipment where residue matters.
- Pressure washers and steam cleaners, to reduce scale build-up.
- Manufacturing processes that need consistent water quality.
AdBlue
AdBlue is 32.5% high-purity urea in de-ionised water. The ISO 22241 standard sets very tight limits on minerals such as calcium, magnesium, sodium and potassium, which is why AdBlue should never be topped up or diluted with tap water.
Storing and handling demineralised water
Because it has so little dissolved in it, demineralised water will pick up contamination from whatever it touches. Handle it with the same care you would give AdBlue:
- Use clean, dedicated containers — HDPE is ideal.
- Keep lids closed to stop dust getting in.
- Don't decant it into containers that held other liquids.
- Use clean pumps, hoses and jugs that aren't shared with oil or coolant.
Something you can do today: check the jug or bottle your workshop uses to top up batteries. If it is an old drink bottle or a jug that gets used for anything else, replace it with a labelled container used only for demineralised water.
Choosing a pack size
Liquidia supplies demineralised water in 20 L containers for workshops and occasional use, and in 1,000 L IBCs for sites that use it in volume, such as truck washes and industrial plants. A 20 L container is easy to handle and store on a shelf. An IBC suits steady use and can be fitted with a tap or pump for dispensing.
If you already buy AdBlue from us, demineralised water can be added to the same order, which saves arranging separate deliveries.
When deciding between the two, think about how quickly you will use it. Demineralised water doesn't break down like AdBlue does in heat, but every time a container is opened there is a chance for dust to get in. A workshop topping up a few batteries a month is usually better served by 20 L containers, while a truck wash or plant using hundreds of litres a week will find an IBC far easier to manage.
How Liquidia can help: We supply demineralised water in 20 L containers and 1,000 L IBCs, alongside our AdBlue range. See our demineralised water page for pack sizes and pricing, or order through the online store.