Onkijärvi is a lake in Sysmä, Finland. This page reports official water-quality measurements, shown as reported.

Is Onkijärvi safe to swim in?

Onkijärvi 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.

Onkijärvi

Sysmä, FinlandView map Directions

Syke publishes the water-quality measurements for Onkijärvi. Here is what has been measured.

Clarity

2.2 m

Clearer than most

Secchi · sampled 2024

Phosphorus

11 µg/L

Typical for Finland

Measured by Syke

Chlorophyll-a

3.8 µg/L

Less algae than most

Measured by Syke

Limited data

See the measurements Directions Where to stay

Onkijärvi in Sysmä, Finland has official water-quality measurements, shown as reported. Water clarity: 2.2 m visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 3.8 µg/L.

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How Onkijärvi is classified

Onkijärvi in Finland 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, 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: the Finnish Environment Institute (Syke) and the ELY Centres.

Onkijärvi is a lake in Sysmä County, Finland.

Source: the Finnish Environment Institute (Syke) and the ELY Centres — not the EPA Water Quality Portal, last sampled 2024-08-07. Methodology: how these readings are compared.

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Onkijärvi is safe to swim in today is a call for the Finnish Environment Institute (Syke) and the ELY Centres and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Onkijärvi

These are the measurements Syke publishes for Onkijärvi. More on the source.

Moderate clarity, visible to about 7.2 ft. Phosphorus 11 µg/L. Chlorophyll-a 3.8 µg/L. TSI 44.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	2.2m	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	11µg/L	Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)	3.8µg/L	Measured, not scored 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.	44	Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic

Moderate nutrients, good water quality

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Answers come straight from the public measurements and survey records on this page.

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Fishing Onkijärvi

→ Onkijärvi fishing regulations (limits, seasons, special rules)

Frequently asked questions about Onkijärvi

Where is Onkijärvi?: Onkijärvi is a lake in Sysmä, Finland. This page reports official water-quality measurements, shown as reported.
What is the water quality of Onkijärvi?: Onkijärvi in Sysmä, Finland has official water-quality measurements, shown as reported. Water clarity: 2.2 m visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 3.8 µg/L.
Is Onkijärvi safe to swim in?: Onkijärvi 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.

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Where this data comes from

3 measurements from 1 monitoring station, 2024. Retrieved from Syke VESLA (not the EPA Water Quality Portal) on 2026-08-16.

Collected and reported by

Finnish Environment Institute (Syke) and ELY Centressyke-vesla3 samples · 2024

Analytical methods

SYKE VESLA

Monitoring station identifiers (1)

82064

Authority classifications are shown as the authority published them. See where the data comes from and data sources.