Grassholme Reservoir
Grassholme Reservoir in Northumberland Durham and Tees, England has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 17.6 µg/L. Chlorophyll-a (algae): 1.7 µg/L.
Why Grassholme Reservoir has no A–F grade
Grassholme Reservoir in England 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 Environment Agency (England).
Grassholme Reservoir is a lake in Northumberland Durham and Tees County, England.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2020-03-16. 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 Grassholme Reservoir
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 17.6 µg/L. Chlorophyll-a: 1.7 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 17.6 µg/L | Not graded |
| Chlorophyll-a (Algae) | 1.7 µg/L | Not graded |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Grassholme Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Grassholme Reservoir in Northumberland Durham and Tees, England — 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 Grassholme Reservoir
Frequently asked questions about Grassholme Reservoir
What is the water quality of Grassholme Reservoir?
- Grassholme Reservoir in Northumberland Durham and Tees, England has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 17.6 µg/L. Chlorophyll-a (algae): 1.7 µg/L.
Is Grassholme Reservoir safe to swim in?
- Grassholme Reservoir 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
87 measurements from 1 monitoring station, 2016–2020. Retrieved from the Environment Agency (England; not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Environment Agency (England)
ea-wqa87 samples · 2016–2020
Monitoring station identifiers (1)
NE-45100099
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: 2020-03-16
Monitoring stations: 1