Water Analysis
Drinking water quality in the European Union is subject to strict regulations. Drinking water must meet stringent requirements for heavy metals, chemical contaminants, and microbiological parameters. Compliance is based on the EU Drinking Water Directive, which is implemented through national legislation in each Member State.
Private well water, recreational water in swimming pools and lakes, as well as cooling and process water, should also be tested regularly to help prevent the spread of Legionella and other pathogens and to ensure safe use.
With its network of accredited laboratories, the Tentamus Group provides comprehensive testing services for drinking water, wastewater, and process water. Our analytical capabilities go far beyond standard rapid tests, delivering reliable, accurate, and actionable results to support regulatory compliance and protect public health.
Who Should Have Their Water Tested by a Laboratory?
- Businesses and operators of water supply systems are required to carry out regular water analyses to ensure compliance with legal requirements and protect water quality.
- Service providers where customers come into contact with water (e.g., dental practices) should have their water tested regularly, as hygiene and safety are of particular importance in these environments.
- Owners and landlords of multi-family residential buildings are responsible for ensuring the quality of the drinking water and are required to arrange regular testing. The local health authority determines which parameters must be analysed in addition to Legionella. Single-family and two-family homes are generally exempt from this obligation.
- Commercial and industrial facilities with central hot water systems are required to have their water tested regularly if they operate a storage drinking water heater or a flow-through drinking water heater with a total capacity exceeding 400 litres, or if the volume of the pipe system between the drinking water heater outlet and the first point of use exceeds 3 litres.
- Large public facilities are required to perform annual Legionella testing, while commercial large-scale facilities must be tested every three years. If the technical action value for Legionella is exceeded, the result must be reported to the relevant health authority. Laboratories are directly obligated to report such exceedances. Test results exceeding other regulatory limits (e.g., for heavy metals or other parameters) must also be communicated to the health authority.
- Operators of water systems are additionally required to report any events that could affect drinking water quality, such as modifications to filtration systems or pipe networks, incidents within protected water zones, or changes in ownership.
Key Water Analysis Parameters at a Glance
Water quality can be influenced by numerous factors, depending on how the water is used. Pathogenic microorganisms and contaminants such as heavy metals are among the key causes of quality deterioration and can pose risks to health and safety. Regular laboratory water analyses enable the early detection of potential contamination and help ensure safe water quality.
Testing for Legionella and Other Microorganisms
In multi-family residential buildings and public facilities, drinking water installations, showers, air conditioning systems, and other systems where water can become aerosolized must be regularly tested for Legionella and other pathogens. Drinking water, in particular, is subject to strict regulatory requirements regarding monitoring and compliance with microbiological limits, as defined by the applicable drinking water regulations.
The responsibility for ensuring that water meets legal requirements for microbiological safety lies with the landlord, owner, and operator of the water system.
As part of our water analysis services, we test for the following microorganisms:
- Total colony count at 22°C and 36°C
- Escherichia coli (E. coli)
- Coliform bacteria
- Enterococci
- Legionella
- Clostridium perfringens
- Pseudomonas aeruginosa
Especially Legionella bacteria represent a significant health risk. They can be inhaled through fine water aerosols and therefore must also be monitored in systems such as showers, air conditioning systems, and other installations where water mist can be generated. According to the German Drinking Water Ordinance (Trinkwasserverordnung, TrinkwV), the technical action value triggering mandatory corrective measures by the operator is 100 CFU (colony-forming units) per 100 ml.
Testing for Lead and Other Contaminants
Until 1970, lead was used for the construction of water pipes. In older buildings, corrosion can therefore cause small amounts of lead to be released into tap water. Even low levels of lead can pose a health risk, particularly for unborn babies and young children. Therefore, the German Drinking Water Ordinance defines strict limit values for drinking water.
In addition to lead, other contaminants can also affect drinking water quality. Property owners and landlords are responsible for ensuring the provision of safe and compliant drinking water in their buildings.
As part of our water analysis, we test for the following contaminants and parameters:
- Sediments and turbidity
- Nitrate and nitrite
- Ammonium
- Heavy metals such as lead, arsenic, and copper
- Pesticides
- Hydrocarbons
Limit Values for Heavy Metals in Drinking Water
The complete table of limit values can be found in Annex II of the German Drinking Water Ordinance (TrinkwV).
Additional Water Tests Required
On 24 June 2023, the German Drinking Water Ordinance (Trinkwasserverordnung, TrinkwV) was updated. It implements the European Drinking Water Directive (EU Directive 2020/2184) and introduces stricter limits for heavy metals, which must be implemented over the coming years, as well as enhanced requirements for action in cases of Legionella contamination.
In addition, new parameters have been included in mandatory drinking water testing. These include:
- Plasticisers
- Industrial chemicals
- Disinfection by-products
- Biotoxins
New Drinking Water Ordinance: Limit Values for Additional Parameters
Analysis of the Mineral Composition of Drinking Water
The mineral composition of water is particularly relevant for mineral water and medicinal water. These types of water are also subject to specific regulations defined by the applicable drinking water legislation.
As part of our drinking water analysis services, we test for the following minerals and parameters:
- Bicarbonate
- Calcium
- Magnesium
- Potassium
- Iron
- Sodium
- Sulfate
- Chloride
- Calcite/calcium carbonate (e.g., limescale formation
Water hardness test
The total hardness of water is based on the concentration of magnesium and calcium ions, calculated as carbonate hardness. Hard water contains higher levels of magnesium and calcium ions than soft water. In Germany, water hardness is expressed in “German degrees of hardness” (°dH) and, according to European legislation, in millimoles of calcium carbonate per liter (mmol CaCO₃/L). The German Drinking Water Ordinance (TrinkwV) does not define any limit values for water hardness; it only classifies water into the following three hardness categories:
Water suppliers are required to publish the total water hardness once a year, provided that it has not changed. If the water hardness changes, the updated information must be published without delay.
Stagnation test
When water stagnates, meaning it remains in the pipes for an extended period of time, for example after a holiday period or a business closure, substances from the pipe materials can migrate into the water and significantly affect the quality of tap water.
During a stagnation test, parameters such as pH value, conductivity, and temperature, as well as relevant heavy metals, are measured and analyzed.
Continuous Water Quality Assurance
For continuous quality assurance of drinking water, bathing water, and process water, regular monitoring of water quality is essential. We offer standardized testing cycles for water analysis in our accredited laboratories, including sampling and sample logistics.
How does sampling for water analysis work?
Sampling for drinking water analysis must be carried out in accordance with the applicable legal requirements and by appropriately qualified and accredited laboratories. This also applies to well water used as drinking water. Similar requirements apply to cooling tower and process water, as well as swimming pool and bathing water, where sampling and testing procedures are regulated by national legislation and relevant technical standards.
In all cases, reliable water quality assessment requires proper sampling procedures carried out by competent and accredited laboratories. We are happy to take care of the entire sampling process to ensure compliant, representative, and meaningful analytical results.
How are water analysis results provided?
The results of the laboratory analyses are compiled by our experts in a clear and easy-to-understand test report. If a technical action threshold is exceeded – for example, for Legionella levels of 100 CFU/100 ml or higher – we, as an accredited laboratory, are legally required to report this immediately to the responsible health authority in accordance with applicable regulations. For unremarkable results, there is no such reporting obligation; however, upon request, we are happy to support you with communication and documentation towards the authorities.
The duration of the analysis depends on the parameters being tested and can range from 4 to 12 days. A Legionella test typically requires 10 to 12 days.
Overview of Tentamus Group laboratories for water analysis
The following Tentamus Group laboratories offer water analysis services:
Frequently Asked Questions
Why should I have my tap water tested?
Tap water intended for human consumption is subject to strict quality requirements throughout the European Union, which must be ensured by water suppliers in accordance with applicable regulations. However, the responsibility of the water supplier generally ends at the point of delivery to the building. Internal plumbing systems, pipe materials, fittings, filtration systems, and other factors within the building can influence water quality before it reaches the consumer.
Ensuring water quality at the point of use is therefore an important responsibility for building owners and is also in the best interest of consumers.
The following factors can affect drinking water quality within a building:
- Dissolved lead, copper, or iron released from pipe materials
- Release of substances such as chromium, zinc, or nickel from fittings
- Increased sodium levels caused by water softening systems
- Microbial contamination due to stagnant water or construction work
- Elevated nitrate or phosphate levels in drinking water from private wells
Regular water analysis at the point of use can help identify potential quality issues, detect contamination sources, and ensure that drinking water remains safe and compliant with applicable requirements.
What are the advantages of laboratory water analysis compared to test kits?
Various rapid test kits are available on the market, allowing consumers to check water quality themselves using test strips. However, these tests provide only limited information, as the water sample is not collected by a trained sampler. This can easily lead to contamination or sampling errors, which may distort the measured values.
To obtain reliable and meaningful analytical results, several quality assurance measures are essential during water analysis:
- Verification of measurement precision – Use of suitable, calibrated equipment and validation of the analytical procedure
- Verification of sample representativeness – Ensuring that sampling is performed at the appropriate point within the water system
- Control of measurement-related risks – Exclusion or consideration of interfering factors, particularly when using test kits or analysing microbiological parameters
- Verification of measurement accuracy – Generation of precise results through validated analytical methods
- Correct interpretation of results – Consideration of relevant influencing factors
- Assessment of result validity – Evaluation of whether measured values are reliable and representative
- Evaluation of potential impacts – Determination of whether elevated values are temporary or indicate a systematic issue
Appropriate response measures – Identification of necessary corrective actions and potential consequences
For official drinking water analyses, such self-tests are generally not accepted by authorities, as the reliability of the results cannot be guaranteed with regard to the aspects mentioned above. Mandatory drinking water testing must therefore be carried out by accredited laboratories with specifically trained samplers.
In addition, test kits provide only an undefined snapshot of the water quality at a specific point in time. The results cannot be reliably traced back to a specific source or cause, meaning that targeted corrective measures cannot be derived.
A professionally planned sampling strategy – considering relevant sampling points and the appropriate type of water sample – ensures reliable and meaningful results. Based on these findings, action plans can be developed, potential contamination sources identified, and measures implemented to maintain water quality or prevent quality deterioration and potential damage to the water installation.
Are Tentamus Group laboratories specifically accredited for water analysis?
All Tentamus Group laboratories that perform water analyses, including sampling, are approved in accordance with applicable drinking water regulations and accredited according to ISO 17025. We provide everything from a single source:
- Expert knowledge and consulting
- Development of tailored water testing profiles
- Sampling planning
- Professional sampling
- Water analysis
- Recommendations for follow-up measures and corrective actions
Are there legal requirements for water that is not used as drinking water?
Yes, legal requirements apply not only to drinking water. Depending on the intended use and the applicable regulations, water can generally be categorized into the following groups:
- Process water / non-potable water (e.g., greywater)
- Swimming pool and bathing water
- Drinking water (e.g., mineral water)
Process water is used, for example, in cooling systems or industrial applications. Water obtained from a private well and used exclusively for garden irrigation – without being connected to the building’s internal plumbing system – is also considered non-potable water.
Each type of water is subject to specific quality and purity requirements defined by applicable legislation and technical standards. Even if water is not intended for human consumption, it must still meet minimum quality requirements to ensure safe use and prevent potential risks.
Water analyses should therefore be carried out by an appropriately qualified and accredited laboratory in accordance with the relevant requirements.
For which types of water is water analysis recommended?
Water analyses are generally recommended for all types of water used by humans or in human-related applications to detect contamination and prevent potential health risks.
These include, in particular:
- Drinking water / mineral water
- Surface water / flowing water
- Swimming pool water / bathing lakes
- Wastewater
- Cooling water / process water
- Groundwater
- Mineral water
- Well water
- Animal drinking water
- Heating system water
- Irrigation water
- Biofilm and pipe sediment (sielhaut) investigations
The different types of water use are subject to specific testing procedures, quality requirements, and legal regulations. We are happy to advise you on the appropriate analysis concept for your needs.
Can tap water be consumed safely?
Yes, tap water can generally be consumed safely within the European Union if it is intended for human consumption and complies with the applicable drinking water quality requirements.
The term “tap water” generally refers to water transported through a pipe system. However, not all water supplied through pipes is automatically suitable for drinking. For example, water used for garden irrigation does not have to meet the same quality requirements as drinking water used for preparing infant formula.
Water intended for human consumption includes water used for drinking, cooking, preparing food and beverages, as well as for personal hygiene, such as showering, and for cleaning objects that come into contact with the body or food.
The quality of drinking water is monitored by water suppliers up to the point of delivery to the building. However, the internal plumbing system can significantly influence water quality, for example through outdated pipe materials, corrosion, or unsuitable materials that may release substances into the water.
Therefore, testing tap water at the point of use through professional water analysis can be beneficial, especially when water is used for drinking or food preparation.