Why rank lakes by phosphorus?

Phosphorus is usually what limits how much algae a lake can grow, so it is the earliest signal that a lake is under nutrient pressure. It is also the measurement these agencies publish most consistently, which makes it the fairest way to compare lakes across a country.

Is a low-phosphorus lake safe to swim in?

Not necessarily. A lightly loaded lake can still carry bacteria, a seasonal algal bloom, or contaminants that a nutrient reading does not cover. Check the local authority notice for the day you plan to go.

What is a typical phosphorus level in Germany?

The median measured lake in Germany reads 9.5 µg/L of total phosphorus. Lakes below roughly 10 µg/L are considered nutrient-poor and usually run clear; above about 30 µg/L a lake is generally nutrient-rich and more likely to green up in summer.

Cleanest lakes in Germany

Cleanest lakes in Germany: 50 named lakes have an official total-phosphorus reading. The 20 below carry the lowest nutrient load — a measurement, not a LakeQuality A–F grade.

Lake map

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Lowest phosphorus readings in Germany

Phosphorus is the nutrient that feeds algae growth, so the lakes at the top of this table are the least loaded ones the Germany monitoring programme has measured. The median measured lake in Germany reads 9.5 µg/L.

Lake	Place	Total phosphorus	Chlorophyll-a	Secchi	Year
Alpsee Bei Schwangau	Ostallgäu	5.0 µg/L	2.0 µg/L	11 m	2023
Eibsee	Garmisch-Partenkirchen	5.0 µg/L	2.0 µg/L	11 m	2022
Murnersee	Schwandorf	5.5 µg/L	2.0 µg/L	8.3 m	2020
Brückelsee	Schwandorf	6.0 µg/L	2.0 µg/L	8.4 m	2020
Königssee	Berchtesgadener Land	6.0 µg/L	2.0 µg/L	8.9 m	2024
Starnberger See	Starnberg	6.0 µg/L	2.0 µg/L	6.2 m	2023
Sylvensteinsee	Bad Tölz-Wolfratshausen	6.0 µg/L	1.0 µg/L	4.0 m	2024
Tegernsee	Miesbach	6.0 µg/L	2.0 µg/L	5.2 m	2023
Trinkwassertalsperre Frauenau	Regen	6.0 µg/L	4.0 µg/L	3.1 m	2022
Weitsee	Traunstein	6.0 µg/L	2.0 µg/L	9.0 m	2023
Wörthsee	Starnberg	6.0 µg/L	2.0 µg/L	4.5 m	2023
Ammersee	Landsberg am Lech	7.0 µg/L	3.0 µg/L	4.0 m	2024
Barmsee	Garmisch-Partenkirchen	7.0 µg/L	5.0 µg/L	6.7 m	2019
Großer Ostersee	Weilheim-Schongau	7.0 µg/L	2.0 µg/L	3.4 m	2023
Kochelsee	Bad Tölz-Wolfratshausen	7.0 µg/L	2.0 µg/L	4.6 m	2022
Obersee	Berchtesgadener Land	7.0 µg/L	3.0 µg/L	12 m	2022
Steinberger See	Schwandorf	7.0 µg/L	2.0 µg/L	6.0 m	2024
Rachelsee	Freyung-Grafenau	7.5 µg/L	7.0 µg/L	1.5 m	2023
Chiemsee	Traunstein	8.0 µg/L	2.0 µg/L	5.5 m	2022
Bannwaldsee	Ostallgäu	9.0 µg/L	6.0 µg/L	3.2 m	2021

Showing 20 of 50 named lakes. Open a county or place page for the rest.

Frequently asked questions

Which lakes in Germany are the cleanest?: 50 named lakes in Germany have an official total-phosphorus reading. This page ranks the 20 lowest. Phosphorus is the nutrient that feeds algae growth, so a low reading means a lightly loaded lake — it is not a swim-safety class and not a LakeQuality A–F grade.
Why rank lakes by phosphorus?: Phosphorus is usually what limits how much algae a lake can grow, so it is the earliest signal that a lake is under nutrient pressure. It is also the measurement these agencies publish most consistently, which makes it the fairest way to compare lakes across a country.
Is a low-phosphorus lake safe to swim in?: Not necessarily. A lightly loaded lake can still carry bacteria, a seasonal algal bloom, or contaminants that a nutrient reading does not cover. Check the local authority notice for the day you plan to go.
What is a typical phosphorus level in Germany?: The median measured lake in Germany reads 9.5 µg/L of total phosphorus. Lakes below roughly 10 µg/L are considered nutrient-poor and usually run clear; above about 30 µg/L a lake is generally nutrient-rich and more likely to green up in summer.