When receiving the results of a water analysis, it can be challenging to understand the numbers and technical terms. This guide helps you interpret the results and provides a clear overview of the most important water quality parameters. You can see the official limit values, what each result means for health, taste, and usage, and what actions you should consider if the values deviate.
The guide is useful both for households using their own well or borehole and for professionals who want a quick reference. Use the table as a practical tool to quickly understand each parameter and find recommended actions.
| Parameter | Limit value | Meaning | Possible causes | Recommended action |
|---|---|---|---|---|
| Appearance & odor | Must be clear and without odor | Changes in taste, color or odor may indicate contamination. | Technical faults, pollution, seawater intrusion. | Inspect installation; repeat analysis if needed. |
| Conductivity | > 30 mS/m | Indicates the amount of dissolved salts. | Seawater intrusion or contamination. | Monitor trend; check borehole and pipes. |
| Nitrate | ≤ 50 mg/l | Health risk for infants, pregnant and breastfeeding women. | Surface water intrusion; agricultural pollution. | Check borehole, well, pump and pipes for leaks. |
| Phosphorus (total) | ≤ 0.15 mg/l | May indicate wastewater or surface water influence. | Contamination from wastewater or runoff. | Inspect for leaks; repeat analysis. |
| pH value | Approx. 6.5–9.5 (guideline) | Affects taste, corrosion and treatment efficiency. | Natural groundwater variation; technical factors. | Adjust via water treatment if necessary. |
| Coliform bacteria | 0 / 100 ml Boil water if > 20 / 100 ml |
Indicates contamination from soil or plant material. | Surface water; leaking installations. | Boil water; locate and fix the source. |
| E. coli | 0 / 100 ml | Fresh contamination from sewage or feces; disease risk. | Sewage; animal or human waste. | Boil all drinking water; remove source; new analysis. |
| Bacteria count 22 °C | ≤ 200 / ml | Natural soil- and water bacteria; rarely harmful. | Organic material in the water. | Investigate source; clean installation. |
| Bacteria count 37 °C | ≤ 5 / ml (waterworks) ≤ 20 / ml (consumer) |
May include pathogenic bacteria. | Surface water; growth in tanks/pipes. | Clean system; repair leaks. |
| Ammonium | ≤ 0.05 mg/l | May stem from decomposition of organic matter. | Natural; biological degradation. | Removed by aeration and filtration. |
| Iron | ≤ 0.2 mg/l | Causes discoloration, metallic taste and staining. | Natural in groundwater. | Removed by aeration and filtration. |
| Manganese | ≤ 0.05 mg/l | Causes black, greasy deposits. | Often occurs with iron. | Removed by aeration and filtration. |
| Hydrogen sulfide (H2S) | ≤ 0.05 mg/l | Smells like rotten eggs; not dangerous in small amounts. | Natural in some regions. | Removed by aeration. |
| Pesticides | ≤ 0.1 µg/l (single) ≤ 0.5 µg/l (total) |
Residues from pesticides; harmful even at low levels. | Agriculture; contamination. | Contact authorities; locate source; new analysis. |
| Water hardness |
|
Indicates calcium and magnesium content; affects taste, soap use and scaling. | Natural groundwater variation. | Consider a water softener for hard water. |
