Mona Reservoir
Juab County, UtahView mapDirections
Utah DWQ publishes the water-quality measurements for Mona Reservoir. Here is what has been measured.
- Mesotrophic
- 50 ft max depth
Mona Reservoir in Juab County, Utah has water-quality measurements published by Utah DWQ, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 53.5 µg/L. Chlorophyll-a (algae): 4.3 µg/L.
Mona Reservoir is a mesotrophic lake in Juab County, Utah with an estimated average depth of about 50 feet. Overall water quality is improving over recent sampling years. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Juab County, Mona Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Utah DWQ, last sampled 2024-09-05. Methodology: how these readings are compared.
What Mona Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyModerate algae
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. Check local advisories before you swim.
Whether Mona Reservoir is safe to swim in today is a call for the Utah Division of Water Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mona Reservoir
These are the measurements Utah DWQ publishes for Mona Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2 ft of visibility. Phosphorus 53.5 µg/L. Chlorophyll-a 4.3 µg/L. TSI 58.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 53.5µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 4.3µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 58 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Mona Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~50 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Utah has not published bathymetry for Mona Reservoir.
Lake Size & Watershed
Watershed (drainage) area
283 sq mi
HydroLAKES / HydroSHEDS
Surface area
1,633 acres
HydroLAKES / HydroSHEDS
Shoreline
11.3 mi
HydroLAKES / HydroSHEDS
Elevation
4,882 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
- Mona ReservoirSemi-private
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Mona Reservoir
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Top-rated places to stay near Mona Reservoir
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Fishing Mona Reservoir
Water quality readings over time
2 seasons of samples on record (2012–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Chlorophyll-a
Stable-0.05 µg/L/yr2 years
Reservoir Info (USACE NID)
Mona Reservoir is a man-made reservoir impounded by the Mona (completed 1895), built primarily for irrigation on the Current Creek; earth-type dam, 28 ft tall and 214 ft long.
- Normal storage
- 19,190 ac-ft
- Max storage
- 30,000 ac-ft
- Drainage area
- 157 sq mi
- Hazard class
- High
- Owner
- CURRENT CREEK IRRIGATION COMPANY
Source: USACE National Inventory of Dams, NID ID UT00215 · Operator website
Nearby Lakes in Juab County
Frequently asked questions about Mona Reservoir
Where is Mona Reservoir?
- Mona Reservoir is a lake in Juab County, Utah. Its water-quality measurements are published by Utah DWQ and shown on this page as reported.
What is the water quality of Mona Reservoir?
- Mona Reservoir in Juab County, Utah has water-quality measurements published by Utah DWQ, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 53.5 µg/L. Chlorophyll-a (algae): 4.3 µg/L.
Is Mona Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Mona Reservoir?
- No published bathymetric survey covers Mona Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 50 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Mona Reservoir?
- Mona Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mona Reservoir.
Can I fish at Mona Reservoir?
- Mona Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Utah's fish and wildlife agency, so check its current regulations before you go.
Explore Mona Reservoir across LakeQuality
2 thermal springs within 6.2 mi, nearest Ray Lunt Spring
Species activity outlook by water temperature and season
Where to stay at Utah's top lakes, each with its readings
Utah's cleanest lakes, ranked on agency measurements
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Other Lakes in Utah
Mesotrophic Lakes in Utah
Where this data comes from
30 measurements from 2 monitoring stations, 2012–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Utah Department Of Environmental Quality
UTAHDWQ_WQX30 samples · 2012–2024
Analytical methods
- Field Measurements
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory