Updated Aug 2026
Arizona Lake Water Quality
229 lakes across 14 counties, 15 with a recent water-quality reading.
Lake Map
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New water-quality readings for Arizona lakes as ADEQ publishes them. Unsubscribe anytime.
Where to stay near Arizona's cleanest lakes
Cabins, resorts, and vacation rentals around Chaparral Park Lake and the other cleanest Arizona lakes pinned on the map. Live availability and prices.
Top-rated places to stay near Chaparral Park Lake
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Explore Arizona Lakes
Arizona reports, fishing & travel
Reservoirs in Arizona
View all 48 reservoirs →48 of 229 Arizona lakes (21%) are man-made reservoirs in the USACE National Inventory of Dams. 37 carry a High or Significant hazard rating. The oldest matched dam dates to 1892.
EPA-Impaired Lakes in Arizona
View all 30 impaired lakes →30 of 229 Arizona lakes (13%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 12 have an approved Total Maximum Daily Load (TMDL) restoration plan.
Arizona Fishing & Recreation
Licenses, regulations, records, and where to fish across Arizona.
Counties
All 14 Arizona counties, ranked by average lake water quality. Compare them against every county nationwide in the county rankings, browse the full directory of lakes, or pick a different state.
15 of the 229 Arizona lakes in this index carry a recent clarity, phosphorus or algae reading, spread over 14 counties. Those readings come from the Arizona Department of Environmental Quality, alongside federal programs and volunteer monitoring networks. The rest are listed for their size, depth and location, with no recent nutrient or algae sampling behind them.
Lake Powell is the largest lake in this index at about 160,784 acres, one of 21 here that clear 500 acres. The rest run smaller, and small and shallow is where nutrient loading shows up first, because there is less water to dilute it and the bottom sediment stays within reach of the sun. Pinal has the lowest nutrient and algae readings on average. With only 14 counties in the state, the cross-county spread is narrower than the within-county spread for most lakes.
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of lakes that fit, with the water quality behind each one.
Source: EPA National Aquatic Resource Surveys and the EPA Water Quality Portal.
More on lake water quality
A data snapshot of the lakes we track: the clearest and the greenest states, and where the water is improving.
How nutrient and algae readings are read against EPA ecoregion condition classes, what each class means in the water, and why a clean reading is not a clearance.
The clearest lakes in America, ranked by measured Secchi depth in feet from EPA monitoring data — and why the famously clear lakes are missing.