Montgomery County Lake Quality
Maryland, 2 lakes — no lake here has enough monitoring data for a grade
Only 2 lakes in Montgomery County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county.
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 Needwood (—) is the cleanest in the county.
Quick Answers for Montgomery County
Planning a trip? Check special fishing regulations for Lake Needwood — or check the official Maryland fishing regulations.
All Lakes in Montgomery County
2 lakes · 0 graded, 2 not rated0 graded lakes · 2 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| NRLake NeedwoodMontgomery | NR | 3 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLong Draught Branch LakeMontgomery | NR | 8.5 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 Maryland
See how Montgomery County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.
Where to stay near Montgomery County
Top-rated places to stay near Montgomery County
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Source: EPA National Aquatic Resource Surveys, 2026.