Skip to main content
LakeQuality

Ullswater

Cumbria and Lancashire, EnglandView mapDirections

EA publishes the water-quality measurements for Ullswater. Here is what has been measured.

Phosphorus
9.1 µg/L
Less phosphorus than most
Measured by EA
Chlorophyll-a
2.6 µg/L
Less algae than most
Measured by EA
  • Limited data

Ullswater in Cumbria and Lancashire, England has official water-quality measurements, shown as reported. Phosphorus: 9.1 µg/L. Chlorophyll-a (algae): 2.6 µg/L.

Loading map…

How Ullswater is classified

Ullswater 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).

Ullswater is a lake in Cumbria and Lancashire County, England.

Source: the Environment Agency (England) — not the EPA Water Quality Portal, last sampled 2026-07-07. Methodology: how these readings are compared.

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Ullswater 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.

Get alerts for Ullswater →

Water quality measurements for Ullswater

These are the measurements EA publishes for Ullswater. More on the source.

No clarity data. Phosphorus 9.1 µg/L. Chlorophyll-a 2.6 µg/L. TSI 38.

Water quality readings
MeasureReadingWhere it sits
Water clarity (Secchi depth)No reading

How deep a black-and-white disk stays visible from the surface. Higher is clearer.

Total phosphorus9.1µg/LMeasured, not scored

The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.

Chlorophyll-a (algae)2.6µg/LMeasured, 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.38Oligotrophic
OligotrophicMesotrophicEutrophicHypereutrophic

Low nutrients, clear water. No reading is a swimming clearance.

Ask about Ullswater

Answers come straight from the public measurements and survey records on this page.

Stays via Stay22

Stays near Ullswater

Compare lakeside cabins, hotels, and vacation rentals near Ullswater in Cumbria and Lancashire, 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.

Top-rated places to stay near Ullswater

Prices for Oct 2–4, 4 adults. Change dates on the map below.

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Follow Ullswater’s readings

Email me when new measurements post for this lake. Updates stay free.


Or email

Fishing Ullswater

Frequently asked questions about Ullswater

Where is Ullswater?

Ullswater is a lake in Cumbria and Lancashire, England. This page reports official water-quality measurements, shown as reported.

What is the water quality of Ullswater?

Ullswater in Cumbria and Lancashire, England has official water-quality measurements, shown as reported. Phosphorus: 9.1 µg/L. Chlorophyll-a (algae): 2.6 µg/L.

Measurements on this page ↑

Is Ullswater safe to swim in?

Ullswater 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.

Swimming on this page ↑

Where this data comes from

169 measurements from 2 monitoring stations, 2016–2026. Retrieved from the Environment Agency (England; not the EPA Water Quality Portal) on 2026-08-16.

Collected and reported by

  • Environment Agency (England)ea-wqa169 samples · 2016–2026
Monitoring station identifiers (2)
  • NW-88010023
  • NW-LSN0176

Authority classifications are shown as the authority published them. See where the data comes from and data sources.