Solent? Maintenance DW25 de-ionised water can be used in lead-acid car batteries, it is also suitable for domestic appliances such as steam irons and steam cleaners, avoids problems caused by scaling. It can also be used as a final rinse in car washing to avoid ?spotting? and is also suitable for rinsing scientific glassware. De-ionised water, when first produced has a neutral pH level of 5.5. The pH level changes as carbon dioxide from the air dissolves in the water and forms carbonic acid (H2CO3). Boiling the water will remove the carbon dioxide and restore the neutral pH. Supplied in 25Ltr drum.