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9 Tips For Optimizing the Quality of Your Lab’s Water

9 Tips For Optimizing the Quality of Your Lab’s Water content piece image

The purity of lab water is critical for ensuring the success of your experiments. When sensitivity is key, water quality is imperative. Simply having an excellent water purification system does not guarantee that contaminant-free water enters your sample vessel.

Water is an excellent solvent for most substances; however, its reactivity makes it susceptible to contamination by bacteria, fungi, chemical solids, gases, vapors and ions. This can result in compromised experimental results, contaminated reagents or damaged equipment.1 All of which means wasted samples, experimental write-offs, and questions about the validity of your results.

With this in mind, we have created a guide to help ensure that your water is always fit for purpose.

Clean your containers 

It may seem obvious but keeping glassware and apparatus clean is essential. Make sure you use a suitable solvent or detergent, rinse thoroughly with pure water and dry well. Detergent carry-over can interfere with downstream applications so ensure there is no residue. Keeping, clearly labelled, dedicated glassware for water transfer and containment will help to reduce cross-contamination.

Water baths and CO2 incubators 

Stagnant water in water baths and incubators is a breeding ground for bacteria and fungi, providing an ideal source of contamination. Use distilled or de-ionized water and change it frequently (keep a logbook to remind yourself and check it regularly). Avoid using tap water as this will accelerate growth of fungi and algae. Routine application of an antibacterial solution will help maintain water standards during water bath use. Adding just a few mL of a good quality disinfectant such as Aquaguard-1 (for incubator water baths) and Aquaguard-2 (for regular water baths) can help prevent contamination by microorganisms such as bacteria and fungi for as long as 6 weeks.

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Look after your equipment 

Change the filters and cartridges on the water filtration system regularly, and always follow the manufacturer’s instructions for keeping the purification system in optimum working condition. Regular maintenance and servicing will ensure your apparatus stays healthy and prolongs the life of the system – all of which saves you money and avoids unnecessary downtime. 

Consider your water’s environment 

Always ensure your laboratory is a clean and tidy environment free from contaminants - good housekeeping should be common practice in a successful laboratory. Most laboratory Standard Operating Procedures (SOPs) will include the instruction to use a solvent or disinfectant spray over all laboratory surfaces before and after experimentation (check your lab’s SOPs to see which solvents/disinfectants should be used). Common solvents include ethanol, 70% industrial methylated spirits (IMS) and isopropyl alcohol (IPA). Alternatively, a safe disinfectant spray such as Pharmacidal can be used daily over benchtops and equipment and offers an alternative to disinfecting with a solvent. 

Avoid plastic tubing

Although plastic tubing can be added to the outlets of many purification devices, this should be avoided wherever possible, as the tubing provides a breeding ground for bacteria. Many manufacturers will offer a more suitable attachment or device to dispense water gently and directly, avoiding overspill and splashes. Leaching is another concern, as plastic tubing can break down over time and contaminate the water supply. 

Collect your pure water correctly 

To avoid introducing bubbles and contamination, collect water gently down the side of your container by tilting the vessel. Pure water is an excellent solvent, capable of dissolving almost anything it encounters; introducing bubbles to the vessel increases the surface area of the water, thus increasing the liability of contamination by dissolvable airborne particles. 

Location of your purification system 

Consider where the water purification device should be located. Avoiding thoroughfares and places with high laboratory traffic can help avoid contamination from volatile molecules (and helps avoid spillages!). To reduce the risk of airborne contaminants avoid positioning the system directly underneath air conditioning units.

Other logistical and design considerations include:
  • The availability of electricity and drainage for your equipment
  • The footprint of the system 
  • The system’s capacity and peak usage demands2 

Flush the system after it has been idle

Try to flush out your purification system on a daily basis. Flushing is especially important if it has been left idle for a significant period of time (even over the weekend). The risk of airborne contaminants increases the longer the system is left idle, so if in doubt always flush through before commencing use.

Do not store high-purity water (if it can be avoided)

There are many sources of contamination in the laboratory and when it comes to storage, the older your water is, the greater the chance of impurities.

Stored water is susceptible to contamination from ions, gases, bacteria, endotoxins, silica, as well as particulates from the container itself1. However, if you have no choice, always ensure your apparatus and storage vessels are appropriate. Containers should be opaque, with a smooth interior wall to discourage bacterial growth, the material must be resistant to leaching and corrosion. Remember to label any storage containers correctly, especially in laboratories which comply to Good Laboratory Practice (GLP), ISO standards, or similar. 


  1. https://academic.oup.com/labmed/article/45/4/e159/2657952 
  2. https://www.orf.od.nih.gov/PoliciesAndGuidelines/Documents/DTR%20White%20Papers/ Laboratory%20Water-Its%20Importance%20and%20Application-March-2013_508.pdf

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