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Selecting the Right Water Purification System for Your Lab

The question of which purification system is most appropriate for a given lab’s needs might leave some scratching their heads

Erica Tennenhouse, PhD

Erica Tennenhouse, PhD, is the managing editor of Clinical Lab Manager.

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The water that flows out of the tap is contaminated with a host of impurities, from organics to inorganics and from bacteria to particulates. Most labs require their water to be purified to some degree, but the question of which purification system is most appropriate for a given lab’s needs might leave some scratching their heads.

According to David Wasescha, a product manager at Labconco (Kansas City, MO), the first question to answer when choosing a water purification system is what level of quality is needed. The three options are Type I, Type II, and Type III, with Type I water being the most pure.

Which level of purity a lab requires depends on the instruments being used and the types of experiments being run, says Wasescha. Most commonly a lab will use Type III water, which is often generated en masse and used to supply equipment like glassware washers and autoclaves and as a source for noncritical solution preparation. Among its applications, Type II water may be used to make buffers, in microbiology culture media, and to prepare reagents for chemical analysis. Type I is generally reserved for more crucial applications, such as HPLC, GC, ICP-MS, and other analytical techniques, as well as PCR, genetic sequencing, and to prepare media for mammalian cell culture and IVF.

A single lab may require more than one type of water. “If many different applications are being done in the same lab, it could be a combination of equipment that will get the job done for everybody,” says Sean Murphy, EU custom project support manager at MilliporeSigma, a business of Merck KGaA, Darmstadt Germany.

Related Article: Buying Tips for Water Purification Systems

Although it may seem simple, labs sometimes get it wrong when it comes to water grade—and that can lead to a host of issues. If, for instance, Type II water is used in a situation that requires Type I water, experimental results may be inaccurate due to contamination. “If it’s a QC lab, it could result in a product being released that shouldn’t have been released,” says Murphy. When substandard water is used to feed lab support instruments, mineral residues may get deposited onto important components and shorten equipment life spans, Wasescha notes.

The reverse situation may also occur. If a lab’s water is too pure for its routine applications—for example, if the water system is producing Type I water when only Type III is needed—it is akin to pouring money down the drain, says Murphy, because the purer the water, the more it costs.

The other question to ask when selecting a water purification system is how much water is needed per day. As Wayne Darsa, director of sales and business development at ELGA LabWater, USA (Woodridge, IL), states, “Beyond water type and amount, everything else is bells and whistles.”

Some of those added extras include a user-friendly interface, water-quality monitors, and customer support, says Murphy, who notes that labs may also opt for the more environmentally friendly water purification systems that are becoming available.

Fortunately, labs do not need to navigate all of the options by themselves. For their larger projects, MilliporeSigma, a business of Merck KGaA, Darmstadt Germany, has three pages’ worth of questions that they pose to their customers in order to orient the decision to the correct piece of equipment. ELGA similarly takes a consultative approach with their customers. “Our approach is to ask the right discovery questions, determine which of our products would meet those requirements, and then together with the scientist decide which of those pieces of equipment make the best sense in terms of technology and cost,” says Darsa.

For additional resources on water purification systems, inclduing useful articles and a list of manufacters, visit