Lough Arrow
Lough Arrow in Sligo, Ireland has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 2.2 µg/L.
Why Lough Arrow has no A–F grade
Lough Arrow 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 Arrow is a lake in Sligo County, Ireland.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-12-05. 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 Arrow
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 13 µg/L. Chlorophyll-a: 2.2 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 13 µg/L | Not graded |
| Chlorophyll-a (Algae) | 2.2 µg/L | Not graded |
| Trophic State Index (TSI) | 40 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lough Arrow
Compare lakeside cabins, hotels, and vacation rentals near Lough Arrow in Sligo, 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 Arrow
Frequently asked questions about Lough Arrow
What is the water quality of Lough Arrow?
- Lough Arrow in Sligo, Ireland has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 2.2 µg/L.
Is Lough Arrow safe to swim in?
- Lough Arrow 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
371 measurements from 5 monitoring stations, 2016–2023. Retrieved from UNEP GEMS/Water GFQA (not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- European Environment Agency
europeanenvironmentagenc371 samples · —
Analytical methods
- GEMStat OPEN / CC BY 4.0
- EPA Ireland WFD lake waterbodies CC BY 4.0
Monitoring station identifiers (5)
IRL00144IRL00145IRL00146IRL00470IRL00471
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: 2023-12-05
Monitoring stations: 5