Hallwilersee
Aargau, SwitzerlandView mapDirections
Eawag publishes the water-quality measurements for Hallwilersee. Here is what has been measured.
- Limited data
Hallwilersee in Aargau, Switzerland has official water-quality measurements, shown as reported. Water clarity: 4.4 m visibility.
How Hallwilersee is classified
Hallwilersee in Switzerland is published with the authority's own measurements and class. The measurements here are published by the agency that samples the lake, as reported. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
LakeQuality publishes no grade of its own beside it. Everything below thathas been measured is reported on this page.
Monitoring: Eawag (the Swiss Federal Institute of Aquatic Science and Technology) and cantonal lake-monitoring programmes.
Hallwilersee is a lake in Aargau County, Switzerland.
Source: Eawag (the Swiss Federal Institute of Aquatic Science and Technology) and cantonal lake-monitoring programmes — not the EPA Water Quality Portal, last sampled 2023-12-18. Methodology: how these readings are compared.
What Hallwilersee is good for
From access and monitoring records, not editorial picks.
- Clear water14.4 ft of visibility
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Hallwilersee is safe to swim in today is a call for Eawag (the Swiss Federal Institute of Aquatic Science and Technology) and cantonal lake-monitoring programmes and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Hallwilersee
These are the measurements Eawag publishes for Hallwilersee. More on the source.
Good clarity, visible to about 14.4 ft. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.4m | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 39 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Hallwilersee
Answers come straight from the public measurements and survey records on this page.
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Fishing Hallwilersee
Frequently asked questions about Hallwilersee
Where is Hallwilersee?
- Hallwilersee is a lake in Aargau, Switzerland. This page reports official water-quality measurements, shown as reported.
What is the water quality of Hallwilersee?
- Hallwilersee in Aargau, Switzerland has official water-quality measurements, shown as reported. Water clarity: 4.4 m visibility.
Is Hallwilersee safe to swim in?
- Hallwilersee has official nutrient and clarity measurements, not a bacteria swim class and not a safety clearance. Algal blooms, currents, and depth are not covered. Always check local notices before swimming.
Explore Hallwilersee across LakeQuality
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Where this data comes from
95 measurements from 1 monitoring station, 2016–2023. Retrieved from the listed programme (not the EPA Water Quality Portal). See data sources on 2026-08-20.
Collected and reported by
- Eawag
eawag-ch95 samples · —
Analytical methods
- Eawag long-term Swiss lake monitoring
Monitoring station identifiers (1)
LakeHallwil
Authority classifications are shown as the authority published them. See where the data comes from and data sources.