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

Is Herajärvi safe to swim in?

Herajärvi 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.

How deep is Herajärvi?

Herajärvi has a maximum depth of 72.2 feet.

Herajärvi

Joensuu, FinlandView map Directions

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

Clarity

6.3 m

Clearer than most

Secchi · sampled 2021

Phosphorus

3.7 µg/L

Less phosphorus than most

Measured by Syke

Chlorophyll-a

1.8 µg/L

Less algae than most

Measured by Syke

Max depth

22 m

Bathymetric survey

72 ft max depth
Limited data

See the measurements Directions Where to stay

Herajärvi in Joensuu, Finland has official water-quality measurements, shown as reported. Water clarity: 6.3 m visibility. Phosphorus: 3.7 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Maximum depth: 72.2 ft.

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How Herajärvi is classified

Herajärvi 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.

Herajärvi is a lake in Joensuu County, Finland with a maximum depth of 72 feet.

Source: the Finnish Environment Institute (Syke) and the ELY Centres — not the EPA Water Quality Portal, last sampled 2021-09-07. Methodology: how these readings are compared.

What Herajärvi is good for

From access and monitoring records, not editorial picks.

Clear water20.7 ft of visibility
Deep water72.2 ft surveyed max depth

Swimming conditions

No reading

Limited data

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

Whether Herajärvi 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 Herajärvi

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

Crystal clear, you can see 20.7 ft down. Phosphorus 3.7 µg/L. Chlorophyll-a 1.8 µg/L. TSI 31.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	6.3m	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	3.7µg/L	Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)	1.8µg/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.	31	Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic

Low nutrients, clear water. No reading is a swimming clearance.

Ask about Herajärvi

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

Lake Details

Max depth

22 m

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Stays near Herajärvi

Compare lakeside cabins, hotels, and vacation rentals near Herajärvi in Joensuu, Finland — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

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Fishing Herajärvi

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

Frequently asked questions about Herajärvi

Where is Herajärvi?: Herajärvi is a lake in Joensuu, Finland. This page reports official water-quality measurements, shown as reported.
What is the water quality of Herajärvi?: Herajärvi in Joensuu, Finland has official water-quality measurements, shown as reported. Water clarity: 6.3 m visibility. Phosphorus: 3.7 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Maximum depth: 72.2 ft.
Is Herajärvi safe to swim in?: Herajärvi 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.
How deep is Herajärvi?: Herajärvi has a maximum depth of 72.2 feet.

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Where this data comes from

8 measurements from 1 monitoring station, 2021. 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-vesla8 samples · 2021

Analytical methods

SYKE VESLA

Monitoring station identifiers (1)

21771

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