Twitchell Reservoir
Twitchell Reservoir in San Luis Obispo County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 156 acres.
- Area
- 156 acres
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Why Twitchell 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 Twitchell 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.
Twitchell Reservoir is a 156-acre lake in San Luis Obispo County, California.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled recent years. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Twitchell 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 Twitchell Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Twitchell Reservoir in San Luis Obispo 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 Twitchell Reservoir
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 156 acres |
No bathymetric survey has been published for Twitchell Reservoir, so its depth is not documented here.
Fishing Twitchell Reservoir
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Frequently asked questions about Twitchell Reservoir
Where is Twitchell Reservoir?
- Twitchell Reservoir is a lake in San Luis Obispo 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 Twitchell Reservoir?
- Twitchell Reservoir in San Luis Obispo County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 156 acres.
Is Twitchell Reservoir safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Twitchell Reservoir is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
Measurements for Twitchell Reservoir come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.