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 Taiwan?

The median measured lake in Taiwan reads 17 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 Taiwan

Cleanest lakes in Taiwan: 21 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 Taiwan

Phosphorus is the nutrient that feeds algae growth, so the lakes at the top of this table are the least loaded ones the Taiwan monitoring programme has measured. The median measured lake in Taiwan reads 17 µg/L.

Lake	Place	Total phosphorus	Chlorophyll-a	Secchi	Year
Jih-Yueh-Tan Reservoir	Nantou	11 µg/L	2.8 µg/L	4.0 m	2020
Te-Chi Reservoir	Taichung	12 µg/L	5.3 µg/L	1.8 m	2020
Li-Yu-Tan Reservoir	Miaoli	13 µg/L	7.5 µg/L	1.8 m	2020
Tseng-Wen Reservoir	Chiayi	13 µg/L	3.6 µg/L	1.6 m	2020
Mu-Tan Reservoir	Pingtung	14 µg/L	6.3 µg/L	2.2 m	2020
Wu-Shan-Tou Reservoir	Tainan	14 µg/L	2.7 µg/L	2.0 m	2020
Nan-Hua Reservoir	Tainan	15 µg/L	3.6 µg/L	1.0 m	2020
A-Kung-Tien Reservoir	Kaohsiung	16 µg/L	7.8 µg/L	1.2 m	2020
Lan-Tan Reservoir	Chiayi City	16 µg/L	6.1 µg/L	2.2 m	2020
Shih-Men Reservoir	Taoyuan	17 µg/L	3.0 µg/L	1.8 m	2020
Hsin-Shan Reservoir	Keelung	17 µg/L	5.7 µg/L	2.0 m	2020
Wu-She Reservoir	Nantou	17 µg/L	4.4 µg/L	2.0 m	2020
湖山水庫	Yunlin	17 µg/L	3.6 µg/L	1.6 m	2020
Yung-Ho-Shan Reservoir	Miaoli	18 µg/L	5.1 µg/L	1.8 m	2020
Jen-Yi-Tan Reservoir	Chiayi	20 µg/L	4.1 µg/L	1.4 m	2020
Cheng-Ching-Hu Reservoir	Kaohsiung	22 µg/L	5.9 µg/L	1.6 m	2020
Pao-Shan Reservoir	Hsinchu	26 µg/L	5.0 µg/L	1.6 m	2020
Pai-Ho Reservoir	Tainan	29 µg/L	7.0 µg/L	1.0 m	2020
Ching-Mien Reservoir	Tainan	30 µg/L	36 µg/L	0.4 m	2020
Ming-Te Reservoir	Miaoli	30 µg/L	48 µg/L	1.0 m	2020

Showing 20 of 21 named lakes. Open a county or place page for the rest.

Frequently asked questions

Which lakes in Taiwan are the cleanest?: 21 named lakes in Taiwan 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 Taiwan?: The median measured lake in Taiwan reads 17 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.