Concordia Parish County Lake Quality
Louisiana, 4 lakes, average grade D (Nutrient-rich)
Concordia Parish County has 4 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. On average, Concordia Parish County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lake St. John (C) is the cleanest in the county.
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Quick Answers for Concordia Parish County
Planning a trip? Check special fishing regulations for Lake St. John — or check the official Louisiana fishing regulations.
All Lakes in Concordia Parish County
4 lakes · 3 graded, 1 not rated3 graded lakes · 1 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | CLake St. JohnConcordia Parish | C | No recent samples | 50 µg/L | No recent samples | No recent samples | Not recorded |
| 2 | DLake ConcordiaConcordia Parish | D | No recent samples | 220 µg/L | No recent samples | No recent samples | Not recorded |
| 3 | DMarengo Bend Southeast of Ferriday LakeConcordia Parish | D | No recent samples | 102 µg/L | No recent samples | No recent samples | Not recorded |
| NRCocodrie Lake South of StacyConcordia Parish | NR | No recent samples | 230 µg/L | No recent samples | No recent samples | Not recorded |
NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
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Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Other Counties in Louisiana
See how Concordia Parish County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 49 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.