Todd Lake-Deep Spot
Todd Lake-Deep Spot in Merrimack County, New Hampshire has a water quality grade of C (Fair). Phosphorus: 15.8 µg/L. Chlorophyll-a (algae): 4.7 µg/L.
- Type
- Mesotrophic
Todd Lake-Deep Spot is a mesotrophic lake in Merrimack County, New Hampshire. Water quality is graded C based on 2 sampling years through 2024. Compared to the 40 other monitored lakes in Merrimack County, Todd Lake-Deep Spot ranks #39 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-06-06. Grade methodology: LakeGrade methodology.
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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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
No clarity data. Phosphorus level: 15.8 µg/L. Chlorophyll-a: 4.7 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 15.8 µg/L | Good |
| Chlorophyll-a (Algae) | 4.7 µg/L | Fair |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Todd Lake-Deep Spot
Compare lakeside cabins, hotels, and vacation rentals near Todd Lake-Deep Spot in Merrimack County, New Hampshire — 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 Todd Lake-Deep Spot
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Fishing Todd Lake-Deep Spot
EPA Impairment Status
Todd Lake-Deep Spot is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700030301-02 · Official waterbody report · Matched by proximity (0.35 km)
County Ranking
Ranked #39 of 41 lakes in Merrimack County
Nearby Lakes in Merrimack County
Frequently asked questions about Todd Lake-Deep Spot
Where is Todd Lake-Deep Spot?
- Todd Lake-Deep Spot is a lake in Merrimack County, New Hampshire. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Todd Lake-Deep Spot?
- Todd Lake-Deep Spot in Merrimack County, New Hampshire has a water quality grade of C (Fair). Phosphorus: 15.8 µg/L. Chlorophyll-a (algae): 4.7 µg/L.
Is Todd Lake-Deep Spot safe to swim in?
- Generally safe for swimming, moderate water quality. Todd Lake-Deep Spot has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 4.7 µg/L. Always check local health department advisories before swimming.
Explore Todd Lake-Deep Spot across LakeGrade
More New Hampshire Lake Rankings
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Full state directory
Other Grade C Lakes in New Hampshire
Mesotrophic Lakes in New Hampshire
Where this data comes from
11 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
1111330011 samples · 2021–2024
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
- CHLOROPHYLL A-B-C DETERMINATION (MODIFIED)
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