Where is Etang du Gallardon?

Etang du Gallardon is a lake in Yvelines, France. This page reports official water-quality measurements, shown as reported.

Is Etang du Gallardon safe to swim in?

Etang du Gallardon 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.

Etang du Gallardon

Yvelines, FranceView map Directions

Eau France publishes the water-quality measurements for Etang du Gallardon. Here is what has been measured.

Clarity

4.2 m

Clearer than most

Secchi · sampled 2025

Chlorophyll-a

4 µg/L

Typical for France

Measured by Eau France

Limited data

See the measurements Directions Where to stay

Etang du Gallardon in Yvelines, France has official water-quality measurements, shown as reported. Water clarity: 4.2 m visibility. Chlorophyll-a (algae): 4 µg/L.

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How Etang du Gallardon is classified

Etang du Gallardon in France 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 and algae (chlorophyll-a), but not phosphorus.

LakeQuality publishes no grade of its own beside it. Everything below thathas been measured is reported on this page.

Monitoring: the French water agencies, via UNEP GEMS/Water.

Etang du Gallardon is a lake in Yvelines County, France.

Source: the French water agencies, via UNEP GEMS/Water — not the EPA Water Quality Portal, last sampled 2025-09-17. Methodology: how these readings are compared.

What Etang du Gallardon is good for

From access and monitoring records, not editorial picks.

Clear water13.6 ft of visibility

Swimming conditions

No reading

Limited data

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

Whether Etang du Gallardon is safe to swim in today is a call for the French water agencies, via UNEP GEMS/Water and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Etang du Gallardon

These are the measurements Eau France publishes for Etang du Gallardon. More on the source.

Good clarity, visible to about 13.6 ft. Chlorophyll-a 4 µg/L. TSI 42.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	4.15m	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus		No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)	4µg/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.	42	Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic

Moderate nutrients, good water quality

Ask about Etang du Gallardon

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

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Stays near Etang du Gallardon

Compare lakeside cabins, hotels, and vacation rentals near Etang du Gallardon in Yvelines, France — 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 Etang du Gallardon

→ Etang du Gallardon fishing regulations (limits, seasons, special rules)

Frequently asked questions about Etang du Gallardon

Where is Etang du Gallardon?: Etang du Gallardon is a lake in Yvelines, France. This page reports official water-quality measurements, shown as reported.
What is the water quality of Etang du Gallardon?: Etang du Gallardon in Yvelines, France has official water-quality measurements, shown as reported. Water clarity: 4.2 m visibility. Chlorophyll-a (algae): 4 µg/L.
Is Etang du Gallardon safe to swim in?: Etang du Gallardon 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.

Explore Etang du Gallardon across LakeQuality

Lake Fishing Forecast

Species activity outlook by water temperature and season

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EU bathing ratings and named-lake measurements

Where this data comes from

11 measurements from 1 monitoring station, 2019–2025. Retrieved from UNEP GEMS/Water GFQA (not the EPA Water Quality Portal) on 2026-08-20.

Collected and reported by

Office français de la biodiversité (Hub'Eau)hubeau-fr11 samples · —

Analytical methods

Hub'Eau / Naïades plans d'eau

Monitoring station identifiers (1)

H3009503

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