Demineralised Water Testing Step-by-Step Methods & Standards Guide
                     Demineralised Water Testing: Step-
by-Step Methods & Standards Guide 
Demineralised Water Testing: Step-by-Step Methods & Standards Guide is essential for 
industries that rely on high-purity water such as pharmaceuticals, power plants, laboratories, 
food processing, and electronics manufacturing. Demineralised (DM) water is produced by 
removing dissolved salts, minerals, and ions, but regular testing is critical to ensure the water 
consistently meets required quality standards. The testing process begins with understanding 
the purpose of DM water in the application, as different industries may have slightly varying 
acceptance limits. Commonly, testing focuses on parameters that indicate ionic purity, 
chemical stability, and absence of contaminants. In the initial stage, samples must be 
collected using clean, contamination-free containers and tested promptly to avoid external 
influence. Among the most important checks are conductivity and resistivity, which directly 
reflect the level of dissolved ions present in the water. Low conductivity and high resistivity 
confirm effective demineralisation and system performance. pH testing is another vital step, 
as DM water can be slightly acidic due to dissolved carbon dioxide, and uncontrolled pH may 
lead to corrosion in pipelines and equipment. At this point in the testing workflow, attention 
is given to dm water testing parameters such as total dissolved solids (TDS), silica content, 
sodium levels, chloride concentration, hardness, and dissolved oxygen, all of which help 
determine whether the water is suitable for its intended industrial use.  
 
Silica testing is especially important in boiler and turbine applications, where even trace 
amounts can cause scaling and efficiency loss. Sodium and chloride levels are monitored to 
detect resin leakage or regeneration issues in ion exchange systems. Hardness testing ensures 
calcium and magnesium ions are effectively removed, preventing scale formation. Dissolved 
oxygen analysis is critical in power and boiler systems, as excess oxygen accelerates 
corrosion. Once individual parameters are tested, results are compared against national and 
international standards such as ASTM, ISO, BIS, or specific industry guidelines. If deviations 
are identified, corrective actions may include resin regeneration, membrane cleaning, or 
system redesign. Documentation and trend analysis form the final step of the testing process, 
enabling operators to track performance over time and predict maintenance needs before 
failures occur. Regular DM water testing not only protects equipment and processes but also 
improves operational efficiency, product quality, and regulatory compliance. By following a 
structured, step-by-step testing approach and adhering to established standards, industries can 
ensure a reliable supply of high-purity demineralised water while minimizing downtime, 
repair costs, and long-term operational risks.