Where is Maardu Järv?

Maardu Järv is a lake in Harju, Estonia. This page reports official water-quality measurements, shown as reported.

Is Maardu Järv safe to swim in?

Maardu Järv 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 Maardu Järv?

Maardu Järv has a maximum depth of 10.8 feet. The lake covers 399.8 acres.

Maardu Järv

Harju, Estonia162 haView map Directions

KAUR publishes the water-quality measurements for Maardu Järv. Here is what has been measured.

Clarity

2.1 m

Clearer than most

Secchi · sampled 2025

Phosphorus

46 µg/L

More phosphorus than most

Measured by KAUR

Chlorophyll-a

13 µg/L

Typical for Estonia

Measured by KAUR

Max depth

3.3 m

Bathymetric survey

Area

162 ha

Surface area

11 ft max depth
Limited data

See the measurements Directions Where to stay

Maardu Järv in Harju, Estonia has official water-quality measurements, shown as reported. Water clarity: 2.1 m visibility. Phosphorus: 46 µg/L. Chlorophyll-a (algae): 13 µg/L. Maximum depth: 10.8 ft. Surface area: 399.8 acres.

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How Maardu Järv is classified

Maardu Järv in Estonia 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 Estonian Environment Agency (Keskkonnaagentuur).

Maardu Järv is a 400-acre lake in Harju County, Estonia with a maximum depth of 11 feet.

Source: the Estonian Environment Agency (Keskkonnaagentuur) — not the EPA Water Quality Portal, last sampled 2025-09-17. 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 Maardu Järv is safe to swim in today is a call for the Estonian Environment Agency (Keskkonnaagentuur) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Maardu Järv

These are the measurements KAUR publishes for Maardu Järv. More on the source.

Moderate clarity, visible to about 6.9 ft. Phosphorus 46 µg/L. Chlorophyll-a 13 µg/L. TSI 55.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	2.1m	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	46µg/L	Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)	13µg/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.	55	Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic

High nutrients, frequent algae, reduced clarity

Ask about Maardu Järv

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

Lake Details

Max depth

3.3 m

Surface area

162 ha

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Fishing Maardu Järv

→ Maardu Järv fishing regulations (limits, seasons, special rules)

Frequently asked questions about Maardu Järv

Where is Maardu Järv?: Maardu Järv is a lake in Harju, Estonia. This page reports official water-quality measurements, shown as reported.
What is the water quality of Maardu Järv?: Maardu Järv in Harju, Estonia has official water-quality measurements, shown as reported. Water clarity: 2.1 m visibility. Phosphorus: 46 µg/L. Chlorophyll-a (algae): 13 µg/L. Maximum depth: 10.8 ft. Surface area: 399.8 acres.
Is Maardu Järv safe to swim in?: Maardu Järv 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 Maardu Järv?: Maardu Järv has a maximum depth of 10.8 feet. The lake covers 399.8 acres.

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Where this data comes from

33 measurements from 2 monitoring stations, 2016–2025. Retrieved from KESE / Estonian Environment Agency (not the EPA Water Quality Portal) on 2026-08-16.

Collected and reported by

Estonian Environment Agency (Keskkonnaagentuur)kese-ee33 samples · 2016–2025

Analytical methods

KESE I-level monitoring

Monitoring station identifiers (2)

SJA7954000
SJA7954003

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