Fairfield County Lake Quality
Connecticut, 9 lakes, average grade C (Fair)
Fairfield County has 9 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. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
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. Saugatuck Reservoir (B) is the cleanest in the county.
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Quick Answers for Fairfield County
Planning a trip? Check special fishing regulations for Saugatuck Reservoir — or check the official Connecticut fishing regulations.
All Lakes in Fairfield County
9 lakes · 4 graded, 5 not rated4 graded lakes · 5 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | BSaugatuck ReservoirFairfield | B | No recent samples | 10 µg/L | 5.9 µg/L | No recent samples | Not recorded |
| 2 | CLake ZoarFairfield | C | No recent samples | 26 µg/L | 14.9 µg/L | No recent samples | Not recorded |
| 3 | DBall PondFairfield | D | No recent samples | 44 µg/L | 3.3 µg/L | No recent samples | Not recorded |
| 4 | DLake KenosiaFairfield | D | No recent samples | 50 µg/L | 17.4 µg/L | No recent samples | Not recorded |
| NRFox Hill LakeFairfield | NR | 3.5 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake CandlewoodFairfield | NR | 8.6 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake NaranekaFairfield | NR | 4.9 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMamanasco LakeFairfield | NR | No recent samples | 42 µg/L | 15.1 µg/L | No recent samples | Not recorded | |
| NRSquantz PondFairfield | NR | 8.2 ft | No recent samples | 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
Which lake suits how you actually use one?
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 Connecticut
See how Fairfield 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.