Walden Pond
Essex County, Massachusetts243 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Mesotrophic
- Impaired · Mercury
- #1 of 7 in the county
- 47 ft max depth
- Limited data
Walden Pond in Essex County, Massachusetts has a water quality grade of A (Excellent). Chlorophyll-a (algae): 3.5 µg/L. Surface area: 243 acres.
- Max depth
- ~47 ft est.
- Area
- 243 acres
- Type
- Mesotrophic
- Chlorophyll-a
- 3.5 µg/L
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Watch Walden Pond’s letter
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Walden Pond is a 243-acre mesotrophic lake in Essex County, Massachusetts with an estimated average depth of about 47 feet. Water quality is graded A based on 1 sampling years through 2017. Compared to the 6 other monitored lakes in Essex County, Walden Pond ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, MassDEP, last sampled 2017-08-31. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The A is nutrients and algae, not a swimming clearance. Walden Pond is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
No clarity data. Chlorophyll-a 3.5 µg/L. TSI 43. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 3.5 µg/L | Good |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~47 ft est. |
| Average Depth | ~19 ft est. |
| Surface Area | 243 acres |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Massachusetts has not published bathymetry for Walden Pond.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Walden Pond
Reservoir Info (USACE NID)
Walden Pond is a man-made reservoir impounded by the Walden Pond Outlet Dam (completed 1890), built primarily for water supply on the Saugus River; earth-type dam, 43 ft tall and 2,220 ft long.
- Surface area
- 243 ac
- Normal storage
- 5,400 ac-ft
- Max storage
- 6,900 ac-ft
- Drainage area
- 1.65 sq mi
- Hazard class
- High
- Owner
- Lynn Water and Sewer Commission
Source: USACE National Inventory of Dams, NID ID MA00246 · Operator website · Matched by proximity (0.29 km)
EPA Impairment Status
Walden Pond is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MA93084 · Official waterbody report
County Ranking
Ranked #1 of 7 lakes in Essex County
Nearby Lakes in Essex County
Frequently asked questions about Walden Pond
Where is Walden Pond?
- Walden Pond is a lake in Essex County, Massachusetts. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Walden Pond?
- Walden Pond in Essex County, Massachusetts has a water quality grade of A (Excellent). Chlorophyll-a (algae): 3.5 µg/L. Surface area: 243 acres.
Is Walden Pond safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Walden Pond is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Walden Pond?
- No published bathymetric survey covers Walden Pond, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 47 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 243 acres.
Explore Walden Pond across LakeQuality
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Where this data comes from
3 measurements from 1 monitoring station, 2017. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Massachusetts Department of Environmental Protection (MassDEP)
MASSDEP3 samples · 2017
Analytical methods
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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
Lake size & watershed from HydroLAKES (HydroSHEDS)