Watson Lake
Yavapai County, Arizona202 acresView mapDirections
ADEQ publishes the water-quality measurements for Watson Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 10 ft max depth
- Public access
- Limited data
Watson Lake in Yavapai County, Arizona has water-quality measurements published by ADEQ, shown here as reported. Phosphorus: 170 µg/L. Surface area: 202 acres.
Watson Lake is a 202-acre highly nutrient-loaded hypereutrophic lake in Yavapai County, Arizona with an estimated average depth of about 10 feet. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 1 other monitored lakes in Yavapai County, Watson Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, ADEQ, last sampled 2026-03-30. Methodology: how these readings are compared.
Watson Lake covers about 200 acres in Yavapai County. It has 2 public boat landings, so a lakefront rental is not the only way to get a boat on the water. Vrbo is where to look for cabins and lake homes around Watson Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Watson Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Watson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
Whether Watson Lake is safe to swim in today is a call for the Arizona Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Watson Lake
These are the measurements ADEQ publishes for Watson Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 170 µg/L. TSI 78.
| 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 | 170µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading 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. | 78 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Watson Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~10 ft est.
Surface area
202 acres
Public access
Yes
Listed by ADEQ
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Arizona has not published bathymetry for Watson Lake.
Lake Size & Watershed
Watershed (drainage) area
44 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.4 mi
HydroLAKES / HydroSHEDS
Elevation
5,164 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Watson Lake - SouthPublic
- Watson Lake - NorthPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Watson Lake
Compare lakeside cabins, hotels, and vacation rentals near Watson Lake in Yavapai County, Arizona — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Watson Lake are listed below.
Top-rated places to stay near Watson Lake
Prices for Oct 30–Nov 1, 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.
Planning a trip? Cabins and lodging at Watson Lake → · more Arizona lake trips
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Fishing Watson Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2013–2025).
Water clarity
Stable2 years
Phosphorus
Stable0 µg/L/yr6 years
Reservoir Info (USACE NID)
Watson Lake is a man-made reservoir impounded by the Granite Creek (completed 1920), built primarily for irrigation on the Granite Creek; arch-type dam, 98 ft tall and 187 ft long.
- Surface area
- 202 ac
- Normal storage
- 4,598 ac-ft
- Max storage
- 4,900 ac-ft
- Drainage area
- 45 sq mi
- Hazard class
- High
- Owner
- CITY OF PRESCOTT
All listed purposes: Irrigation;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID AZ00020 · Operator website
EPA Impairment Status
Watson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation, Other.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit AZL15060202-1590_00 · Official waterbody report
Nearby Lakes in Yavapai County
Frequently asked questions about Watson Lake
Where is Watson Lake?
- Watson Lake is a lake in Yavapai County, Arizona. Its water-quality measurements are published by ADEQ and shown on this page as reported.
What is the water quality of Watson Lake?
- Watson Lake in Yavapai County, Arizona has water-quality measurements published by ADEQ, shown here as reported. Phosphorus: 170 µg/L. Surface area: 202 acres.
Is Watson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Watson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
How deep is Watson Lake?
- No published bathymetric survey covers Watson Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 10 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 202 acres.
Are there boat ramps on Watson Lake?
- Watson Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Watson Lake - South, Watson Lake - North. Public access is listed as yes.
Can I fish at Watson Lake?
- Watson Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Arizona's fish and wildlife agency, so check its current regulations before you go.
Explore Watson Lake across LakeQuality
Planning a trip around Montezuma Castle?
Watson Lake is about 34 miles from Montezuma Castle National Monument. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Montezuma Castle →More lakes in Arizona
Other Lakes in Arizona
Hypereutrophic Lakes in Arizona
Where this data comes from
14 measurements from 3 monitoring stations, 2024–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Great Lakes Environmental Center
GLEC8 samples · 2025–2026 - AZDEQ_SW
AZDEQ_SW6 samples · 2024–2025
Analytical methods
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 300.0 ~ EPA; Determination of Inorganic Anions by Ion Chromatography
- SM 4500 PE
- EPA 365.1
Monitoring station identifiers (3)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory