Grassholme Reservoir
Northumberland Durham and Tees, EnglandView mapDirections
EA publishes the water-quality measurements for Grassholme Reservoir. Here is what has been measured.
- Limited data
Grassholme Reservoir in Northumberland Durham and Tees, England has official water-quality measurements, shown as reported. Phosphorus: 17.6 µg/L. Chlorophyll-a (algae): 1.7 µg/L.
How Grassholme Reservoir is classified
Grassholme Reservoir in England 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 phosphorus and algae (chlorophyll-a), but not water clarity.
LakeQuality publishes no grade of its own beside it. Everything below thathas been measured is reported on this page.
Monitoring: the Environment Agency (England).
Grassholme Reservoir is a lake in Northumberland Durham and Tees County, England.
Source: the Environment Agency (England) — not the EPA Water Quality Portal, last sampled 2020-03-16. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grassholme Reservoir is safe to swim in today is a call for the Environment Agency (England) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Grassholme Reservoir
These are the measurements EA publishes for Grassholme Reservoir. More on the source.
No clarity data. Phosphorus 17.6 µg/L. Chlorophyll-a 1.7 µg/L. TSI 41.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 17.6µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 1.7µg/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. | 41 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Frequently asked questions about Grassholme Reservoir
Where is Grassholme Reservoir?
- Grassholme Reservoir is a lake in Northumberland Durham and Tees, England. This page reports official water-quality measurements, shown as reported.
What is the water quality of Grassholme Reservoir?
- Grassholme Reservoir in Northumberland Durham and Tees, England has official water-quality measurements, shown as reported. 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 shown as the authority published them. See where the data comes from and data sources.