Category: Wet Labs
Level: Bronze
Author: Bianca Schell, Kerstin Hermuth Kleinschmidt
The Impact: Water savings
Details
The purer the water, the more water and other resources are needed to produce it. Depending on the purity grade, purifying 1 litre of water can require 3–5 litres of tap water. By selecting the lowest suitable water grade for each task, one can signifcantly reduce water, energy and material (such as filters and bottles) use.
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Checklist
Understand and explain the different water grades in your lab
☐ Identify which water types are available in your lab (e.g. tap, Type III (RO), Type II (pure), Type I (ultrapure).
Match processes to the lowest suitable water grade
☐ For common procedures in your lab (e.g. buffer preparation, glassware rinsing, media preparation, cleaning, molecular biology, cell culture), decide which minimum water grade is sufficient.
☐ Create a short guidance list or table (e.g. “Application → Minimum water grade”) and share it with the group.
☐ Optionally add short reminder like “Use only when ultrapure water is really needed”.
Integrate water grade guidance into training and protocols
☐ Include water purity guidance in your onboarding or local training materials (e.g. slides, lab manual, SOPs).
☐ Update at least a few key protocols or SOPs to explicitly state the required water grade (e.g. “Use deionised water (Type II)”, “Tap water is sufficient”).
Reflect water purity in methods and documentation
☐ When writing protocols or publications, add the water purity grade to the methods section.
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How will this be reviewed?
Describe how you have ensured that the lowest suitable water grades are used in your lab. At a minimum, you should:
- Explain which water grades are available and how they are used.
- Describe how you decided which water grade is sufficient for typical procedures.
- Explain how this information is communicated to lab members (e.g. training, guidance tables, labels, updated protocols).
Provide evidence, for example:
- A short guidance table or slide showing common applications and the corresponding minimum water grade.
- Examples of training materials or lab manuals mentioning water grades.
- Example protocols or methods sections (internal or published) where the water purity grade is explicitly stated.
- Optionally, photos of labels on purification systems indicating water grade and/or typical uses.
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For auditors
Obligatory (all obligatory boxes are ticked → Positive)
☐ There is a simple overview of water grades available in the lab and guidance on their typical uses. At least some common lab procedures have documented guidance on the minimum water grade needed.
☐ Example protocols or methods sections include water purity.
Optional
☐ Water purity guidance appears in training materials, lab manuals, or SOPs.
☐ Labels on purification systems indicate water grade (e.g. “Tap water”, “Deionised/Type II”, “Ultrapure/Type I”).
Questions for audit online meeting:
- Which water grades are available in your lab, and where?
- How did you decide which water grade is sufficient for typical procedures?
- Where can lab members find this information (e.g. guidance tables, SOPs, training)?
- Are people encouraged not to use ultrapure water when a lower grade is sufficient
