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 Latvia?

The median measured lake in Latvia reads 28.5 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 Latvia

Cleanest lakes in Latvia: 33 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 Latvia

Phosphorus is the nutrient that feeds algae growth, so the lakes at the top of this table are the least loaded ones the Latvia monitoring programme has measured. The median measured lake in Latvia reads 28.5 µg/L.

Lake	Place	Total phosphorus	Chlorophyll-a	Secchi	Year
Sventes Ezers	—	10 µg/L	2.8 µg/L	6.6 m	2023
Busnieku Ezers	—	11 µg/L	4.4 µg/L	1.5 m	2022
Dridza Ezers A Dala	—	12 µg/L	3.9 µg/L	5.2 m	2022
Ricu Ezers	—	14 µg/L	3.7 µg/L	3.6 m	2023
Laukezers	—	15 µg/L	3.3 µg/L	7.5 m	2023
Daugulu Ezers	—	15 µg/L	4.8 µg/L	1.7 m	2023
Raznas Ezers	—	15 µg/L	4.0 µg/L	3.9 m	2021
Usmas Ezers	—	16 µg/L	4.7 µg/L	2.1 m	2023
Liduksnas Ezers	—	18 µg/L	5.2 µg/L	2.1 m	2021
Augstrozes Lielezers	—	20 µg/L	5.9 µg/L	1.3 m	2023
Saukas Ezers	—	20 µg/L	8.2 µg/L	2.2 m	2023
Lielais Gusena Ezers	—	22 µg/L	5.3 µg/L	3.0 m	2022
Kalna Ezers	—	22 µg/L	6.4 µg/L	2.6 m	2022
Osvas Ezers	—	25 µg/L	9.1 µg/L	1.3 m	2022
Ungura Rustega Ezers	—	25 µg/L	31 µg/L	1.2 m	2023
Micanu Ezers	—	26 µg/L	5.4 µg/L	1.4 m	2022
Meiranu Ezers	—	29 µg/L	11 µg/L	1.1 m	2022
Raiskuma Ezers	—	29 µg/L	13 µg/L	1.6 m	2023
Kiruma Ezers	—	30 µg/L	8.8 µg/L	1.9 m	2023
Aijazu Ezers	—	32 µg/L	17 µg/L	0.8 m	2023

Showing 20 of 33 named lakes. Open a county or place page for the rest.

Frequently asked questions

Which lakes in Latvia are the cleanest?: 33 named lakes in Latvia 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 Latvia?: The median measured lake in Latvia reads 28.5 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.