Crystal Lake
Montcalm County, Michigan709 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Mesotrophic
- #1 of 4 in the county
- 70 ft max depth
- Public access
Crystal Lake in Montcalm County, Michigan has a water quality grade of A (Excellent). Water clarity: 10 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 2.2 µg/L. Maximum depth: 70 ft. Surface area: 708.5 acres.
- Clarity
- 10 ft
- Typical in September
- 57°F
- Max depth
- 70 ft
- Area
- 709 acres
- Type
- Mesotrophic
- Phosphorus
- 9 µg/L
- Chlorophyll-a
- 2.2 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
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Watch Crystal Lake’s letter
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Crystal Lake is a 709-acre mesotrophic lake in Montcalm County, Michigan with a maximum depth of 70 feet. Water quality is graded A based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 3 other monitored lakes in Montcalm County, Crystal Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-09-15. Grade methodology: LakeQuality methodology.
What Crystal Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10 ft of visibility
- Deep water70 ft surveyed max depth
Swimming Safety
Grade onlyLow algae
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)
Good clarity, visible to about 10 ft. Phosphorus 9 µg/L. Chlorophyll-a 2.2 µg/L. TSI 39. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 9 µg/L | Good |
| Chlorophyll-a (Algae) | 2.2 µg/L | Good |
| Trophic State Index (TSI) | 39 | Mesotrophic |
Moderate nutrients, good water quality
Water Temperature
Crystal Lake typically sits around 57°F at the surface in September. Summer average is about 55°F. Usually warmest in Sep (about 57°F) and coldest in May (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 527 field readings (2011–2014) via the EPA Water Quality Portal. See the full Crystal Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 70 ft |
| Surface Area | 709 acres |
| Public Access | Yes |
Fishing Crystal Lake
Water Quality Trend: ↓ Declining
Based on 8 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.513 m/yr | 8 |
| Phosphorus | ↓ Declining | +0.54 µg/L/yr | 7 |
| Chlorophyll-a | ↓ Declining | +0.32 µg/L/yr | 7 |
County Ranking
Ranked #1 of 4 lakes in Montcalm County
Nearby Lakes in Montcalm County
Frequently asked questions about Crystal Lake
Where is Crystal Lake?
- Crystal Lake is a lake in Montcalm County, Michigan. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Crystal Lake?
- Crystal Lake in Montcalm County, Michigan has a water quality grade of A (Excellent). Water clarity: 10 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 2.2 µg/L. Maximum depth: 70 ft. Surface area: 708.5 acres.
Is Crystal Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Crystal Lake?
- Crystal Lake typically sits around 57°F at the surface in September, from 527 EPA Water Quality Portal field readings (2011–2014). That is a typical value for the month, not a live reading.
How deep is Crystal Lake?
- Crystal Lake has a maximum depth of 70 feet. The lake covers 708.5 acres.
Explore Crystal Lake across LakeQuality
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Where this data comes from
154 measurements from 1 monitoring station, 2016–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS154 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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.