Sam Rayburn Reservoir
San Augustine County, TexasView mapDirections
Nutrients and algae sit mid-range for this region.
- Eutrophic
- Impaired · Algal growth
- #1 of 3 in the county
- Public access
Sam Rayburn Reservoir in San Augustine County, Texas has a water quality grade of C (Fair). Water clarity: 3.9 ft visibility. Phosphorus: 27.5 µg/L. Chlorophyll-a (algae): 18.6 µg/L.
- Clarity
- 3.9 ft
- Type
- Eutrophic
- Phosphorus
- 27.5 µg/L
- Chlorophyll-a
- 18.6 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
Stays via Stay22
Stays near Sam Rayburn Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Sam Rayburn Reservoir in San Augustine County, Texas — 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 Sam Rayburn Reservoir
Prices for Sep 11–13, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip? Cabins and lodging at Sam Rayburn Reservoir → · more Texas lake trips
Watch Sam Rayburn Reservoir’s letter
Email me if this lake’s grade moves. Grades stay free.
Or email
Sam Rayburn Reservoir is a productive, nutrient-rich eutrophic lake in San Augustine County, Texas. Water quality is graded C based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 12 public boat landings. Compared to the 2 other monitored lakes in San Augustine County, Sam Rayburn Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, TCEQ, last sampled 2025-12-10. Grade methodology: LakeQuality methodology.
What Sam Rayburn Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch12 documented ramps
Swimming Safety
Grade onlyAlgae risk
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 C is nutrients and algae, not a swimming clearance. Sam Rayburn Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, dioxins, mercury. Check local advisories before you swim.
Water Quality Grade: C (Fair)
Murky, only visible to about 3.9 ft. Phosphorus 27.5 µg/L. Chlorophyll-a 18.6 µg/L. TSI 56. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.9 ft | Not graded |
| Phosphorus | 27.5 µg/L | Good |
| Chlorophyll-a (Algae) | 18.6 µg/L | Fair |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
→ Sam Rayburn Reservoir water level: the live USGS gauge reading
Recreation & Access
- Cassells-Boykin Park (East)Public
- Boat Ramp RoadPublic
- Caney Creek ParkPublic
- Hanks Creek Park (North)Public
- Hanks Creek Park (South)Public
- Monterrey ParkPublic
Showing 6 of 12 documented landings from the USGS National Boat Ramps inventory.
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Sam Rayburn Reservoir
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.06 m/yr | 5 |
| Phosphorus | ↓ Declining | +4.02 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -1.17 µg/L/yr | 5 |
EPA Impairment Status
Sam Rayburn Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit TX-0610_03 · Official waterbody report
County Ranking
Ranked #1 of 3 lakes in San Augustine County
Nearby Lakes in San Augustine County
Frequently asked questions about Sam Rayburn Reservoir
Where is Sam Rayburn Reservoir?
- Sam Rayburn Reservoir is a lake in San Augustine County, Texas. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Sam Rayburn Reservoir?
- Sam Rayburn Reservoir in San Augustine County, Texas has a water quality grade of C (Fair). Water clarity: 3.9 ft visibility. Phosphorus: 27.5 µg/L. Chlorophyll-a (algae): 18.6 µg/L.
Is Sam Rayburn Reservoir safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Sam Rayburn Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, dioxins, mercury. Check local advisories before you swim.
Are there boat ramps on Sam Rayburn Reservoir?
- Sam Rayburn Reservoir has 12 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Cassells-Boykin Park (East), Boat Ramp Road, Caney Creek Park, Hanks Creek Park (North), among others. Public access is listed as yes.
Explore Sam Rayburn Reservoir across LakeQuality
12.8 mi away
Species activity outlook by water temperature and season
Where to stay at Texas's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
Texas's cleanest and most-polluted lakes, ranked
More Texas Lake Rankings
Other Grade C Lakes in Texas
Eutrophic Lakes in Texas
Where this data comes from
53 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Texas Commission on Environmental Quality
TCEQMAIN53 samples · 2020–2025
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
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory