Lake Morongo
Lake Morongo in Riverside County, California has a water quality grade of D (Nutrient-rich). Phosphorus: 60 µg/L.
- Type
- Eutrophic
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Lake Morongo →
Lake Morongo is a productive, nutrient-rich eutrophic lake in Riverside County, California. Water quality is graded D based on 1 sampling years through 2026.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2026-06-09. Grade methodology: LakeGrade methodology.
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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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
No clarity data. Phosphorus level: 60 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 60 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lake Morongo
Compare lakeside cabins, hotels, and vacation rentals near Lake Morongo in Riverside County, California — 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 grade measures nutrients and algae, not lodging — cabins and rentals around Lake Morongo are listed below.
Top-rated places to stay near Lake Morongo
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Fishing Lake Morongo
County Ranking
Ranked #1 of 1 lakes in Riverside County
Nearby Lakes in Riverside County
Frequently asked questions about Lake Morongo
Where is Lake Morongo?
- Lake Morongo is a lake in Riverside County, California. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Morongo?
- Lake Morongo in Riverside County, California has a water quality grade of D (Nutrient-rich). Phosphorus: 60 µg/L.
Is Lake Morongo safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Lake Morongo has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
Explore Lake Morongo across LakeGrade
More California Lake Rankings
Other Grade D Lakes in California
Eutrophic Lakes in California
Where this data comes from
68 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Morongo Band of Mission Indians
MORONGO1_WQX68 samples · 2020–2026
Analytical methods
- 4500 P B ~ Phosphorus, sample preparation method
- 4500 P F ~ Phosphorus in Water by Colorimetry Automated Ascorbic Acid Method
- Total Nitrogen by Calculation
- 2130 B ~ Nephelometric Method
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.