Zelwa
Zelwa in LW30685, Poland has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 4.5 m visibility.
- Clarity
- 4.5 m
Why Zelwa has no A–F grade
Zelwa in Poland is published with the authority's own measurements, not a LakeQuality letter. official authority class; not a LakeQuality A–F letter Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
A letter on the LakeQuality scale would be an invention, not an official class. Everything below that has been measured is still reported on this page.
Monitoring: the Chief Inspectorate of Environmental Protection (Główny Inspektorat Ochrony Środowiska).
Zelwa is a lake in LW30685 County, Poland.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2026-06-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Zelwa
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 14.6 ft. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.45 m | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Zelwa
Compare lakeside cabins, hotels, and vacation rentals near Zelwa in LW30685, Poland — 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.
Top-rated places to stay near Zelwa
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Fishing Zelwa
Frequently asked questions about Zelwa
What is the water quality of Zelwa?
- Zelwa in LW30685, Poland has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 4.5 m visibility.
Is Zelwa safe to swim in?
- Zelwa 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 Zelwa across LakeGrade
More lakes in Poland
Where this data comes from
2 measurements from 1 monitoring station, 2026. Retrieved from GIOŚ lake monitoring (not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Główny Inspektorat Ochrony Środowiska
gios-pjwp2 samples · —
Analytical methods
- GIOŚ PJWP lake monitoring
Monitoring station identifiers (1)
PL07S0802_0023
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See methodology and data sources.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2026-06-22
Monitoring stations: 1