Lough Castlebar
Lough Castlebar in Mayo, Ireland has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 16.5 µg/L. Chlorophyll-a (algae): 2.5 µg/L.
Why Lough Castlebar has no A–F grade
Lough Castlebar in Ireland 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 phosphorus and algae (chlorophyll-a), but not water clarity.
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 Environmental Protection Agency of Ireland, via UNEP GEMS/Water, with WFD lake names from EPA Ireland.
Lough Castlebar is a lake in Mayo County, Ireland.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2022-10-05. 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 Lough Castlebar
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 16.5 µg/L. Chlorophyll-a: 2.5 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 16.5 µg/L | Not graded |
| Chlorophyll-a (Algae) | 2.5 µg/L | Not graded |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Lough Castlebar
Compare lakeside cabins, hotels, and vacation rentals near Lough Castlebar in Mayo, Ireland — 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 Lough Castlebar
Frequently asked questions about Lough Castlebar
What is the water quality of Lough Castlebar?
- Lough Castlebar in Mayo, Ireland has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 16.5 µg/L. Chlorophyll-a (algae): 2.5 µg/L.
Is Lough Castlebar safe to swim in?
- Lough Castlebar 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
12 measurements from 1 monitoring station, 2018–2022. Retrieved from UNEP GEMS/Water GFQA (not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- European Environment Agency
europeanenvironmentagenc12 samples · —
Analytical methods
- GEMStat OPEN / CC BY 4.0
- EPA Ireland WFD lake waterbodies CC BY 4.0
Monitoring station identifiers (1)
IRL00453
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: 2022-10-05
Monitoring stations: 1