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 Poland?

The median measured lake in Poland reads 47.5 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 Poland

Cleanest lakes in Poland: 721 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 Poland

Phosphorus is the nutrient that feeds algae growth, so the lakes at the top of this table are the least loaded ones the Poland monitoring programme has measured. The median measured lake in Poland reads 47.5 µg/L.

Lake	Place	Total phosphorus	Chlorophyll-a	Secchi	Year
Bobięcińskie Wielkie	LW20887	13 µg/L	5.2 µg/L	5.3 m	2025
Piaseczno	LW10828	13 µg/L	4.1 µg/L	5.1 m	2024
Śmiadowo	LW10594	13 µg/L	4.9 µg/L	3.3 m	2024
Komorze	LW10579	15 µg/L	3.7 µg/L	3.4 m	2025
Lubicko Wielkie	LW10581	15 µg/L	5.6 µg/L	2.9 m	2025
Jegocin	LW30265	15 µg/L	3.6 µg/L	3.6 m	2026
Chlewo	LW20899	16 µg/L	9.2 µg/L	3.0 m	2025
Jaroszewskie	LW10287	16 µg/L	3.2 µg/L	3.5 m	2025
Barlineckie	LW11025	16 µg/L	3.0 µg/L	3.3 m	2025
Lubikowskie	LW10332	16 µg/L	3.7 µg/L	6.3 m	2025
Piaszno	LW20312	16 µg/L	4.0 µg/L	6.9 m	2024
Lednica	LW10157	17 µg/L	—	2.4 m	2024
Mamry	LW30544	17 µg/L	—	3.2 m	2026
Karskie Wielkie	LW10937	17 µg/L	—	3.1 m	2024
Ostrowica	LW10808	17 µg/L	7.0 µg/L	3.5 m	2025
Spore	LW10527	17 µg/L	4.2 µg/L	3.8 m	2024
Pluszne	LW30390	18 µg/L	5.2 µg/L	3.6 m	2025
Dymno	LW20265	18 µg/L	4.1 µg/L	4.8 m	2025
Lipińskie	LW30243	18 µg/L	—	1.9 m	2024
Muchocińskie	LW10321	18 µg/L	—	2.4 m	2024

Showing 20 of 721 named lakes. Open a county or place page for the rest.

Frequently asked questions

Which lakes in Poland are the cleanest?: 721 named lakes in Poland 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 Poland?: The median measured lake in Poland reads 47.5 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.