L Pontchartrain Lake
L Pontchartrain Lake in St. Tammany Parish County, Louisiana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.6 ft visibility.
- Clarity
- 3.6 ft
Why L Pontchartrain Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: 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 L Pontchartrain Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
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.
L Pontchartrain Lake is a lake in St. Tammany Parish County, Louisiana.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2021-12-07. Grade methodology: LakeGrade methodology.
Watch L Pontchartrain Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedBacteria advisory
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for L Pontchartrain Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 3.6 ft. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.6 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near L Pontchartrain Lake
Compare lakeside cabins, hotels, and vacation rentals near L Pontchartrain Lake in St. Tammany Parish County, Louisiana — 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 L Pontchartrain Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Fishing L Pontchartrain Lake
EPA Impairment Status
L Pontchartrain Lake 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 LA041001_00 · Official waterbody report · Matched by proximity (0.03 km)
Graded lakes near L Pontchartrain Lake
L Pontchartrain Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in St. Tammany Parish County
Frequently asked questions about L Pontchartrain Lake
Where is L Pontchartrain Lake?
- L Pontchartrain Lake is a lake in St. Tammany Parish County, Louisiana. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for L Pontchartrain Lake?
- L Pontchartrain Lake in St. Tammany Parish County, Louisiana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.6 ft visibility.
Is L Pontchartrain Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. L Pontchartrain Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore L Pontchartrain Lake across LakeGrade
More Louisiana Lake Rankings
Other Lakes in Louisiana
St. John the Baptist Parish County · Not rated
St. Charles Parish County · Not rated
St. John the Baptist Parish County · Not rated
Tangipahoa Parish County · Not rated
St. John the Baptist Parish County · Not rated
Tangipahoa Parish County · Not rated
Eutrophic Lakes in Louisiana
Where this data comes from
11 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- USGS Louisiana Water Science Center
USGS-LA11 samples · 2020–2021
Analytical methods
- Secchi disk method
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