Jericho Lake-Deep Spot
Coos County, New Hampshire132 acresView mapDirections
NHDES publishes the water-quality measurements for Jericho Lake-Deep Spot. Here is what has been measured.
- Mesotrophic
- Impaired · Biotoxins
- Public access
- Limited data
Jericho Lake-Deep Spot in Coos County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 13 µg/L. Surface area: 132 acres.
Jericho Lake-Deep Spot is a 132-acre mesotrophic lake in Coos County, New Hampshire. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 12 other monitored lakes in Coos County, Jericho Lake-Deep Spot ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-06-23. Methodology: how these readings are compared.
What Jericho Lake-Deep Spot is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyBacteria advisory
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Jericho Lake-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for biotoxins, mercury. Check local advisories before you swim.
Whether Jericho Lake-Deep Spot is safe to swim in today is a call for the New Hampshire Department of Environmental Services and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Jericho Lake-Deep Spot
These are the measurements NHDES publishes for Jericho Lake-Deep Spot, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 13 µg/L. TSI 41.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 13µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 41 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Jericho Lake-Deep Spot
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
132 acres
Public access
Yes
Listed by NHDES
No bathymetric survey has been published for Jericho Lake-Deep Spot, so its depth is not documented here.
Recreation & Access
- Jericho Mountain State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fishing Jericho Lake-Deep Spot
Reservoir Info (USACE NID)
Jericho Lake-Deep Spot is a man-made reservoir impounded by the Dead River Dam 1 (completed 1970), built primarily for flood risk reduction on the Jericho Brook; earth-type dam, 47 ft tall and 3,035 ft long.
- Surface area
- 132 ac
- Normal storage
- 1,240 ac-ft
- Max storage
- 4,720 ac-ft
- Drainage area
- 6.48 sq mi
- Hazard class
- High
- Owner
- NH DNCR
Source: USACE National Inventory of Dams, NID ID NH00473 · Operator website · Matched by proximity (0.18 km)
EPA Impairment Status
Jericho 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
Designated uses not supporting: Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK400010606-01 · Official waterbody report
Nearby Lakes in Coos County
Frequently asked questions about Jericho Lake-Deep Spot
Where is Jericho Lake-Deep Spot?
- Jericho Lake-Deep Spot is a lake in Coos County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Jericho Lake-Deep Spot?
- Jericho Lake-Deep Spot in Coos County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 13 µg/L. Surface area: 132 acres.
Is Jericho Lake-Deep Spot safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Jericho Lake-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for biotoxins, mercury. Check local advisories before you swim.
Are there boat ramps on Jericho Lake-Deep Spot?
- Jericho Lake-Deep Spot has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Jericho Mountain State Park. Public access is listed as yes.
Can I fish at Jericho Lake-Deep Spot?
- Jericho Lake-Deep Spot has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by New Hampshire's fish and wildlife agency, so check its current regulations before you go.
Explore Jericho Lake-Deep Spot across LakeQuality
More lakes in New Hampshire
Other Lakes in New Hampshire
Mesotrophic Lakes in New Hampshire
Where this data comes from
8 measurements from 1 monitoring station, 2023–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
111133008 samples · 2023–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory