Large Lake
Large Lake in Herts and North London, England has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 360 µg/L. Chlorophyll-a (algae): 38.7 µg/L.
Why Large Lake has no A–F grade
Large Lake 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).
Large Lake is a lake in Herts and North London County, England.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2017-08-03. 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 Large Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 360 µg/L. Chlorophyll-a: 38.7 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 360 µg/L | Not graded |
| Chlorophyll-a (Algae) | 38.7 µg/L | Not graded |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Large Lake
Compare lakeside cabins, hotels, and vacation rentals near Large Lake in Herts and North London, 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 Large Lake
Frequently asked questions about Large Lake
What is the water quality of Large Lake?
- Large Lake in Herts and North London, England has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 360 µg/L. Chlorophyll-a (algae): 38.7 µg/L.
Is Large Lake safe to swim in?
- Large Lake 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
8 measurements from 2 monitoring stations, 2017. Retrieved from the Environment Agency (England; not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Environment Agency (England)
ea-wqa8 samples · 2017
Monitoring station identifiers (2)
TH-PGWL0200TH-PGWL0201
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: 2017-08-03
Monitoring stations: 2