Lake Mary
Salt Lake County, UtahView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- #2 of 3 in the county
- Limited data
Lake Mary in Salt Lake County, Utah has a water quality grade of A (Excellent). Water clarity: 26.9 ft visibility. Phosphorus: 3.1 µg/L. Chlorophyll-a (algae): 0.7 µg/L.
- Clarity
- 26.9 ft
- Type
- Oligotrophic
- Phosphorus
- 3.1 µg/L
- Chlorophyll-a
- 0.7 µg/L
- Trend
- ↓ Declining
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Stays near Lake Mary
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Watch Lake Mary’s letter
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Lake Mary is a cold, clear oligotrophic lake in Salt Lake County, Utah. Water quality is graded A based on 1 sampling years through 2024. Overall water quality is declining over recent sampling years. Compared to the 2 other monitored lakes in Salt Lake County, Lake Mary ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Utah DWQ, last sampled 2024-08-07. Grade methodology: LakeQuality methodology.
What Lake Mary is good for
From access and monitoring records, not editorial picks.
- Clear water26.9 ft of visibility
- Camping2 public campgrounds nearby
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Crystal clear, you can see 26.9 ft down. Phosphorus 3.1 µg/L. Chlorophyll-a 0.7 µg/L. TSI 26. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 26.9 ft | Not graded |
| Phosphorus | 3.1 µg/L | Not graded |
| Chlorophyll-a (Algae) | 0.7 µg/L | Good |
| Trophic State Index (TSI) | 26 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Recreation & Access
Public campgrounds near Lake Mary
- Albion Basin Cg2.2 km
- Redman Cg3.2 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fishing Lake Mary
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Chlorophyll-a | ↓ Declining | +0.03 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Lake Mary is a man-made reservoir impounded by the Lake Mary-Phoebe (completed 1915), built primarily for water supply on the Trib. To Big Cottonwood Cr.; gravity-type dam, 72 ft tall and 330 ft long.
- Normal storage
- 742 ac-ft
- Drainage area
- 1 sq mi
- Hazard class
- High
- Owner
- SALT LAKE CITY CORPORATION
Source: USACE National Inventory of Dams, NID ID UT00172 · Operator website · Matched by proximity (0.5 km)
County Ranking
Ranked #2 of 3 lakes in Salt Lake County
Nearby Lakes in Salt Lake County
Frequently asked questions about Lake Mary
Where is Lake Mary?
- Lake Mary is a lake in Salt Lake County, Utah. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Mary?
- Lake Mary in Salt Lake County, Utah has a water quality grade of A (Excellent). Water clarity: 26.9 ft visibility. Phosphorus: 3.1 µg/L. Chlorophyll-a (algae): 0.7 µg/L.
Is Lake Mary safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Are there campgrounds on Lake Mary?
- Lake Mary has 2 public campgrounds from USGS The National Map within 5 km, including Albion Basin Cg, Redman Cg. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Lake Mary across LakeQuality
3 thermal springs within 23.2 mi, nearest Midway Hot Springs
Species activity outlook by water temperature and season
Where to stay at Utah's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
Utah's cleanest and most-polluted lakes, ranked
More Utah Lake Rankings
Other Grade A Lakes in Utah
Oligotrophic Lakes in Utah
Where this data comes from
5 measurements from 1 monitoring station, 2012–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Utah Department Of Environmental Quality
UTAHDWQ_WQX5 samples · 2012–2024
Analytical methods
- Field Measurements
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Public campgrounds from USGS The National Map Structures, within about 3 miles