San Luis Reservoir
San Luis Reservoir in Merced County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 138 acres.
- Area
- 138 acres
Next lake in Merced County
Swipe left or right on this bar to open the next or previous lake.
Why San Luis Reservoir has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For San Luis Reservoir, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by your state environmental agency and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
San Luis Reservoir is a 138-acre lake in Merced County, California.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch San Luis Reservoir water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for San Luis Reservoir
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near San Luis Reservoir
Compare lakeside cabins, hotels, and vacation rentals near San Luis Reservoir in Merced 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.
Top-rated places to stay near San Luis Reservoir
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 138 acres |
No bathymetric survey has been published for San Luis Reservoir, so its depth is not documented here.
Fishing San Luis Reservoir
Nearby Lakes in Merced County
Frequently asked questions about San Luis Reservoir
Where is San Luis Reservoir?
- San Luis Reservoir is a lake in Merced County, California. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for San Luis Reservoir?
- San Luis Reservoir in Merced County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 138 acres.
Is San Luis Reservoir safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. San Luis Reservoir is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore San Luis Reservoir across LakeQuality
More California Lake Rankings
Other Lakes in California
Where this data comes from
Measurements for San Luis Reservoir come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.