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LakeQuality

The single cleanest lake in Texas is Lake Hawkins, with the highest combined water quality score in our 2026 dataset (grade A). Cleanliness is measured by Secchi depth (clarity), total phosphorus, and chlorophyll-a — all sourced from EPA Water Quality Portal and state agency sampling. The full top 25 ranked list appears below.

The "cleanest" ranking on LakeQuality starts from the A–F letter — nutrients and algae scored against EPA National Lakes Assessment 2022 ecoregion classes. Secchi clarity is shown and used only as a tiebreak, not as a graded input. The cleanest Texas lake on the current data is Lake Hawkins (A).

The top of the cleanest-lakes list is dominated by deep, glacial, cold-water basins — the same basins that produce the A-grade bracket overall. The pattern is not coincidence: depth and watershed land-use are the dominant inputs to water-clarity and nutrient-loading both.

RankLakeCountyGradeClarityPhosphorusChlorophyll-aArea
1Lake HawkinsWoodA6.7 ft20 µg/L6.9 µg/L1,064 acres
2Hubbard Creek ReservoirStephensB3.1 ft30 µg/L9 µg/L14,922 acres
3Lake Fk ReservoirWoodC1.9 ft53 µg/L-
4Lynchburg ReservoirHarrisC1.1 ft98.5 µg/L5.9 µg/L200 acres
5Lake Bob SandlinCampC3.9 ft30 µg/L19.5 µg/L-
6B A Steinhagen ReservoirJasperC1.1 ft60 µg/L10.9 µg/L14,700 acres
7Lake GilmerUpshurC3 ft38 µg/L24.9 µg/L895 acres
8Sam Rayburn ReservoirSan AugustineC3.9 ft27.5 µg/L18.6 µg/L-
9Purtis Creek LakeHendersonC3 ft45 µg/L25.7 µg/L349 acres
10Lake Tyler ESmithC3.3 ft25 µg/L25.8 µg/L3,584 acres
11Lake TylerSmithC3.4 ft30 µg/L22 µg/L3,584 acres
12Lewisville LakeDentonD1.8 ft43 µg/L26.8 µg/L23,280 acres
13Grapevine LakeTarrantD2.4 ft48 µg/L18.5 µg/L7,380 acres
14Lake TawakoniHuntD1.5 ft100 µg/L32 µg/L-
15Ray Roberts LakeCookeD2.6 ft30 µg/L15 µg/L29,350 acres
16Lake ConroeMontgomeryD2.2 ft70 µg/L-
17Lake WhitneyBosqueD3.1 ft40 µg/L19.3 µg/L-
18Lake GladewaterUpshurD3 ft35 µg/L28.2 µg/L435 acres
19Possum Kingdom LakeStephensD3.9 ft30 µg/L14.5 µg/L-
20Lake BrownwoodBrownD1.8 ft45 µg/L22.6 µg/L7,300 acres
21Lake Ray HubbardRockwallF2 ft64 µg/L31.8 µg/L-
22Lake Houston S Union Pacific Rr BridgeHarrisF1.3 ft210.5 µg/L36.7 µg/L-
23Lavon LakeCollinF1.4 ft106.5 µg/L48 µg/L21,400 acres
24Lake PalestineSmithF2 ft48 µg/L56.5 µg/L-
25Lake MurvaulPanolaF2.1 ft53.9 µg/L65.3 µg/L-

Get updates when Texas's cleanest-lake list changes

New nutrient and algae samples can move a lake up or down this ranking. Unsubscribe anytime.

Clearest lakes in Texas by water clarity

“Clearest” ranks by Secchi depth — how far you can see into the water — which can differ from the combined cleanliness score above. The clearest water in Texas is Brandy Branch Reservoir at 12 ft of Secchi visibility.

  1. 1. Brandy Branch Reservoir12 ft, Harrison County
  2. 2. Canyon Lake10.8 ft, Comal County
  3. 3. Waco Lake9.8 ft, McLennan County
  4. 4. Lake Alan Henry9.4 ft, Garza County
  5. 5. Lake Daingerfield Headwaters8.5 ft, Morris County
See the full clearest-lakes ranking for Texas

Frequently Asked Questions

What is the cleanest lake in Texas?

Lake Hawkins has the highest water quality score in our 2026 Texas dataset (grade A). Lakes are graded A to F on nutrients and algae — total phosphorus, total nitrogen, chlorophyll-a, and turbidity — measured against the EPA National Lakes Assessment 2022 condition classes for that lake's own ecoregion, so a lake is judged against the lakes it would naturally resemble. Cleanliness here means a low nutrient load and little algae, measured directly from EPA and state DNR samples; where two lakes tie on the letter, the deeper Secchi reading ranks first.

What is the most polluted lake in Texas?

Among monitored Texas lakes, Lake Opines ranks among the most polluted by combined phosphorus and chlorophyll-a load. See our full ranking on the most-polluted-lakes trend page for state-by-state details.

Where in Texas has the cleanest water?

Texas's clearest waters are concentrated in deeper, lower-nutrient glacial basins with forested or low-agriculture watersheds. Among the current top-ranked lakes above, counties like Smith, Wood, and Stephens produce the highest-scoring lakes.

What is the clearest lake in Texas?

Brandy Branch Reservoir is the clearest lake in Texas by water clarity, with a Secchi depth of 12 feet — the deepest transparency in our 2026 dataset. "Clearest" ranks by Secchi depth (how far you can see into the water) specifically, while "cleanest" combines clarity with phosphorus and chlorophyll-a. See our full clearest-lakes ranking for Texas for the top 25 by Secchi clarity.

Are these lakes safe to swim in?

Not on the letter alone. An A or B is a nutrients-and-algae classification, not a swimming clearance — it does not measure E. coli, cyanotoxins, or a posted beach closure, and a lake with low chlorophyll-a can still bloom. Always check current posted advisories before swimming: water quality changes seasonally, especially in late summer when blue-green algae bloom risk peaks.

How are these grades calculated?

The letter is nutrients and algae — phosphorus, nitrogen, chlorophyll-a, and turbidity — scored against EPA National Lakes Assessment 2022 condition classes for that lake’s ecoregion, not a Texas-only 0–100 average and not an equal-weight mean with Secchi. Water clarity is shown; it is not scored. Lakes without enough recent sampling are UNRATED. Our methodology page has the full rubric.

What are the top 5 cleanest lakes in the US?

There is no single national ranking of cleanest lakes — each state agency uses different metrics. Crater Lake (Oregon) is widely cited as the clearest US lake, with Secchi depths over 30 m. Lake Tahoe and Lake Superior are also top-tier nationally. Within Texas, the 25 lakes ranked above are the graded lakes with the highest letters in our 2026 dataset.

How we rank cleanest lakes

Cleanliness here means three things working together:

  • Secchi clarity — how deep you can see into the water (in feet). Greater depth = clearer water = lower suspended sediment and algae.
  • Total phosphorus — the nutrient that fuels algae. Lower phosphorus levels mean less algae growth potential.
  • Chlorophyll-a — the green pigment in algae. Direct measurement of how much algae is currently in the water.

Each signal is normalized against Texas state norms and combined into a single 0–100 score. The lakes above are sorted by that combined score.Full methodology →

Where to stay near Texas's cleanest lakes

Compare cabins, resorts, and rentals around Lake Hawkins and the other lakes in this ranking, with live availability and prices for your trip. Each pin on the map is one of the ranked lakes above.

Top-rated places to stay near Lake Hawkins

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.

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Source: EPA National Aquatic Resource Surveys, 2026.