Types of Water

Lab water is classified into different types based on its purity levels and the intended use. These types include:

Type 1 (Ultra-Pure) Water

Technician at a ResinTech facility
Type 1 water is the highest purity level and is suitable for critical laboratory applications, such as molecular biology, cell culture, and analytical techniques like high-performance liquid chromatography (HPLC) and mass spectrometry.

Type 2 Pure Water

Industrial water treatment tanks
Type 2 water is of lower purity compared to Type 1 and is commonly used in general laboratory applications like buffer and media preparation, glassware rinsing, and some analytical techniques where lower purity standards are acceptable.

Type 3 General-Purpose Water

Stainless steel water treatment tanks
Type 3 water is the least pure among the three types and is suitable for non-critical laboratory applications, such as heating baths, equipment rinsing, and other general lab tasks.

Resistivity and Conductivity

The resistivity of water is a measure of its ability to resist the flow of electric current. It is an intrinsic property of the material itself.
Electrical resistance (ohm) icon.

Unit

Moist filter media sitting in warehouses for months or years becomes a breeding ground for bacteria - the opposite of what filtration should accomplish.
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Relationship

Higher resistivity indicates a poorer conductor,
and vice versa.
Water pollution icon.

Water Quality

In Water quality assessments, low resistivity may indicate the presence of ions or impurities that enhance the water's conductivity.
Type I Water
Type II Water
Type III Water
Resistivity (measured as megaohm-cm at 25°C)
>18 MΩ-cm
1.0 to 18.0MΩ-cm
0.1 to 1.0 MΩ-cm
Conductivity (microsiemens/cm at 25°C)
<.055 μS/cm
.055 to 1 μS/cm
1 to 10 μS/cm
Type I Water
Resistivity (measured as megaohm-cm at 25°C)
>18 MΩ-cm
Conductivity (microsiemens/cm at 25°C)
<.055 μS/cm
Type II Water
Resistivity (measured as megaohm-cm at 25°C)
1.0 to 18.0MΩ-cm
Conductivity (microsiemens/cm at 25°C)
.055 to 1 μS/cm
Type III Water
Resistivity (measured as megaohm-cm at 25°C)
0.1 to 1.0 MΩ-cm
Conductivity (microsiemens/cm at 25°C)
1 to 10 μS/cm
For water purity assessment, especially in the context of lab water quality, high resistivity and low conductivity are desirable characteristics. Ultra-pure water used in laboratories often has high resistivity, indicating low levels of dissolved ions and impurities.
It's important to note that these resistivity ranges are general guidelines, and specific applications or standards may have slightly different requirements. Laboratories often use one or more lab water purification systems, such as reverse osmosis (RO), deionization (DI), and polishing techniques, to achieve the desired water quality for each type. Regular monitoring of water quality parameters, including resistivity and conductivity, is essential to ensure consistency and reliability in laboratory applications.
Person holding a bottle of treated water

Total Organic Carbons (TOC)

TOC serves as a critical metric for measuring organic impurities in water. Keeping TOC levels low is imperative, especially in applications where organic contamination could introduce variability and compromise the reliability of results.
The intricate relationship between TOC, resistivity, and conductivity highlights their collective role in maintaining water purity. Regular monitoring of these parameters is fundamental for laboratories committed to upholding the highest standards of precision and reliability in their scientific endeavors.

Purification Methodologies

Water purification methods play a vital role in achieving the desired water quality. Common methodologies include:
Breathable fabric icon.

Reverse Osmosis (RO)

Removes ions and larger particles, forming the foundation for subsequent purification steps.
Ion icon.

Deionization (DI)

Eliminates ionized impurities and thereby increased resistivity. This method is often used in tandem with RO, providing an additional layer of purification for enhanced water quality.
Ultrafiltration icon.

Ultrafiltration

Targets particles and macromolecules, contributing significantly to the overall purity of the water.
UV light icon.

UV Oxidation

Focused on microbial control (bacteria, viruses, and fungi), UV disinfection is a physical process that utilizes the germicidal properties of ultraviolet light to disrupt the DNA or RNA of microorganisms, preventing their ability to replicate and causing their inactivation.
Understanding the synergies among these purification methods equips scientists with insights into developing a comprehensive water purification system tailored to the specific needs of their laboratory.
Typical Labaratory Application
It's important to note that the suitability of each type of water for specific applications may vary depending on the specific requirements of the experiment or analysis.Laboratories often use a combination of water types to meet the diverse needs of different applications within their workflows.

Type I Water

Scientist holding a test tube and plant

Molecular Biology

Removes ions and larger particles, forming the foundation for subsequent purification steps.
Female scientist measuring a sample

High-Performance Liquid
Chromatography (HPLC)

Required for precise separations and analyses in HPLC applications.
Mass spectrometer

Mass spectrometry

Required for precise separations and analyses in HPLC applications.
Appliance protected by treated water

Atomic Absorption Spectroscopy
(AAS)

Used for trace metal analysis, demanding high purity for reliable results.

Type II Water

Scientists reviewing data on a tablet

Buffer Preparation

Suitable for general laboratory tasks, including the preparation of buffers for various experiments.
Close-up of laboratory glassware

Glassware Rinsing

Ideal for rinsing laboratory glassware to prevent contamination in subsequent experiments.
Sterilizing medical instruments in a laboratory

Autoclave Operations

Used in autoclaves for sterilization purposes.
Working together to prove a new theory

General Laboratory Analysis

Appropriate for routine analyses where ultra-high purity is not a strict requirement.

Type III Water

Pouring a laboratory water sample

Equipment Rinsing

Suitable for rinsing laboratory equipment and containers.
Laboratory water bath heating samples

Heating Baths

Used in heating baths for experiments that do not require ultra-high purity water.
Female technician working at laboratory bench

Non-Critical Laboratory Applications

Appropriate for various non-critical tasks where water purity is less critical.
Blue cartridge water filter housings

Hydra Systems

The Hydra DI System is a pre-assembled cartridge system that provides deionized water using a staged filtration process. Suitable for pre-treatment or applications requiring Type Il water quality, Hydra systems include cartridges and a resistivity indicator for a total turnkey system.

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