How Water Quality Affects Osmosis Cleaning
Why ppm Values and Water Hardness Determine Cleaning Results
- Expert Knowledge
- Josha Kneiber, Geschäftsführer hyCLEANER
Water quality is one of the most important prerequisites for successful cleaning results with osmosis water. Only when lime, minerals, and other dissolved substances are sufficiently removed from the water can PV systems, glass surfaces, and facades be cleaned without residue. Water hardness and the so-called ppm value play a particularly crucial role. They determine how clean the purified water is and how effectively osmosis cleaning works.
Key Points
- Water quality in osmosis cleaning is measured in ppm. The lower the value, the purer the water.
- For cleaning PV systems and facades, a value below 30 ppm is recommended. For glass surfaces, the value should be below 15 ppm.
- Lime and minerals in water can leave residues and accelerate recontamination.
- Regional water hardness affects the performance and settings of osmosis systems.
- Tap water is generally the most suitable source water for osmosis systems.
Why Water Quality Is Critical for Osmosis Cleaning
Normal tap water contains various minerals, salts, and lime components. When evaporating, these substances remain on the cleaned surface. This creates fine residues to which new dirt can adhere more easily.
Professional cleaning therefore requires water that is as pure as possible. The fewer dissolved substances the water contains, the cleaner the surface dries. At the same time, cleaning intervals are extended because dirt reaccumulates less quickly.
For those who want to better understand the fundamentals of water treatment, the article on “Osmosis Cleaning in Industry” provides further information on how purified water and reverse osmosis work.
What ppm Means in Osmosis Cleaning
Water quality is measured in ppm. The abbreviation stands for “parts per million” and describes the amount of dissolved substances in water.
As a general rule: the lower the ppm value, the higher the water quality. A low value means that only a few minerals and salts remain in the water. This purified water is exactly what is needed for professional cleaning of PV systems, glass surfaces, and facades.
Recommended ppm Values for Professional Cleaning
Different applications have different water quality requirements. The following guideline values are recommended for professional cleaning results:
- below 30 ppm for PV systems and facades
- below 15 ppm for glass surfaces
These values ensure that the water dries almost without residue and leaves no visible lime or mineral deposits.
From our experience cleaning PV systems, glass facades, and industrial surfaces, we achieve the best results with purified water values below 20 ppm. Particularly with glass surfaces, even higher values can lead to visible drying residues.
How different water treatment systems affect water quality and operating costs is shown in the comparison “Reverse Osmosis vs. Mixed Bed Resin”.
Why Low ppm Values Are So Important
No lime spots on surfaces
Low ppm values prevent visible lime and mineral deposits after water dries.
Reduced re-soiling
Without residues, dust and dirt have significantly fewer adhesion points on the surface.
Consistent cleaning results
Purified water ensures streak-free cleaning and a clean appearance.
Gentle cleaning of sensitive surfaces
High water quality enables effective cleaning without aggressive chemicals.
Better light transmission for PV modules
Clean module surfaces support optimal utilization of incident sunlight.
Water quality plays a particularly important role in cleaning solar modules. Why purified water is especially suitable for solar cleaning is explained in the article “Why Osmosis Water Is the Best Cleaning Solution for PV Systems”.
How Water Hardness Affects Osmosis Cleaning
Water hardness varies considerably by region. In Germany, values range from approximately 70 ppm for soft water to around 500 ppm for very hard water.
The higher the water hardness, the more minerals and lime must be removed from the water. This increases the demands on water treatment, and the osmosis system settings must be adjusted accordingly.
Consideration of local water quality is therefore particularly important for professional cleaning systems.
How Water Quality Is Measured in Osmosis Cleaning
In practice, water quality is monitored using a TDS meter or conductivity meter. These devices display the ppm value of the water and enable quick verification of purified water quality.
Before cleaning begins, both tap water and the osmosis water produced are often measured. This allows verification that the osmosis system is achieving the desired water quality.
Typical Measuring Devices for Water Monitoring
- TDS meter for measuring ppm value
- Conductivity meter for monitoring water quality
- Laboratory water analysis for special applications
Typical ppm Values in Practice
- Tap water: Depending on the region, values typically range between 70 and 500 ppm.
- Soft water: In regions with soft water, values around 70 to 150 ppm are often measured.
- Hard water: Hard tap water can reach values of 300 to 500 ppm or more.
- Osmosis water: Professional osmosis systems typically reduce values to below 20 ppm.
- Purified water for glass surfaces: For high-quality glass cleaning, values below 15 ppm are typically targeted.
Why Tap Water Is the Best Foundation for Osmosis Systems
Osmosis systems are designed for treating normal tap water. This provides controllable water quality and consistent baseline values for filter technology.
Well water or other natural water sources, on the other hand, often contain additional suspended solids and contaminants. These can burden filter systems more quickly and increase maintenance requirements.
For reliable and economical operation, using tap water as the source for purified water production is therefore recommended.
Conclusion: Why Water Quality Determines Cleaning Success
Water quality has a direct impact on osmosis cleaning results. Low ppm values ensure residue-free surfaces, less recontamination, and higher cleaning quality.
Those who want to professionally clean PV systems, glass surfaces, or facades should pay attention not only to cleaning technology but also to the quality of the water used. Only the combination of appropriate water treatment and modern cleaning technology enables optimal results.
Further information on available water systems for professional cleaning can be found on our Add-Ons page.
About the Author
Josha Kneiber, Geschäftsführer hyCLEANER
Josha Kneiber is Managing Director of hyCLEANER and has been working with professional cleaning solutions for photovoltaic systems, glass surfaces, and facades for many years. His areas of expertise include robot-assisted cleaning, osmosis cleaning systems, and the development of efficient cleaning concepts for commercial and industrial applications.
The water quality recommendations described in this article are based on practical experience from cleaning projects and the use of professional osmosis systems in daily operations.
Areas of Expertise:
PV Cleaning | Osmosis Cleaning | Cleaning Robotics | Cleaning Systems
Last professionally reviewed: June 10, 2026
Sources and Technical Foundations
The values cited in this article are based on:
- practical experience from hyCLEANER in cleaning PV systems, glass surfaces, and facades
- manufacturer specifications for professional purified water systems
- recommendations from building cleaning practice
- technical information from DVGW (German Technical and Scientific Association for Gas and Water)
FAQ: Frequently Asked Questions About Water Quality in Osmosis Cleaning
What does ppm mean for osmosis water?
ppm describes the amount of dissolved substances in water. The lower the value, the purer the water and the better it is suited for professional cleaning.
What ppm values are recommended for PV systems?
For cleaning PV systems, a value below 30 ppm is recommended. This allows the water to dry almost without residue.
What ppm value is optimal for osmosis cleaning?
For cleaning PV systems and facades, a value below 30 ppm is generally recommended. For glass surfaces, values below 15 ppm are considered ideal.
Why does tap water leave residues?
Tap water contains lime, minerals, and salts. These remain on the surface when evaporating and can promote recontamination.
Why is well water unsuitable for osmosis systems?
Well water often contains additional suspended solids and contaminants that can burden or clog filter systems more quickly.
Why does water hardness affect osmosis cleaning?
The higher the water hardness, the more minerals and lime must be removed from the water. This increases the demands on water treatment.