Newton Reservoir
Cache County, Utah297 acresView mapDirections
Utah DWQ publishes the water-quality measurements for Newton Reservoir. Here is what has been measured.
- Oligotrophic
Newton Reservoir in Cache County, Utah has water-quality measurements published by Utah DWQ, shown here as reported. Water clarity: 15.4 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Surface area: 297 acres.
Newton Reservoir is a 297-acre cold, clear oligotrophic lake in Cache County, Utah. Overall water quality is declining over recent sampling years. Compared to the 8 other monitored lakes in Cache County, Newton Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Utah DWQ, last sampled 2021-10-06. Methodology: how these readings are compared.
Newton Reservoir covers about 300 acres in Cache County. If you are planning to stay, you can search lake houses and cabins around Newton Reservoir on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Newton Reservoir is good for
From access and monitoring records, not editorial picks.
- Clear water15.4 ft of visibility
Swimming conditions
Readings onlyLow algae
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. Check local advisories before you swim.
Whether Newton Reservoir is safe to swim in today is a call for the Utah Division of Water Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Newton Reservoir
These are the measurements Utah DWQ publishes for Newton Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 15.4 ft down. Phosphorus 26 µg/L. Chlorophyll-a 1.7 µg/L. TSI 42.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 15.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 26µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.7µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 42 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Newton Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
297 acres
No bathymetric survey has been published for Newton Reservoir, so its depth is not documented here.
Stays via Stay22
Stays near Newton Reservoir
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Top-rated places to stay near Newton Reservoir
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Fishing Newton Reservoir
Water Quality Trend: Worsening
Based on 6 years of monitoring (2014–2021).
Water clarity
Stable6 years
Phosphorus
Worsening+3.5 µg/L/yr2 years
Chlorophyll-a
Worsening+0.7 µg/L/yr2 years
Reservoir Info (USACE NID)
Newton Reservoir is a man-made reservoir impounded by the Newton Dam (completed 1946), built primarily for irrigation on the Clarkston Creek; earth-type dam, 104 ft tall and 3,340 ft long.
- Surface area
- 297 ac
- Normal storage
- 5,594 ac-ft
- Max storage
- 5,594 ac-ft
- Drainage area
- 55.99 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
Source: USACE National Inventory of Dams, NID ID UT10129 · Operator website
Nearby Lakes in Cache County
Frequently asked questions about Newton Reservoir
Where is Newton Reservoir?
- Newton Reservoir is a lake in Cache County, Utah. Its water-quality measurements are published by Utah DWQ and shown on this page as reported.
What is the water quality of Newton Reservoir?
- Newton Reservoir in Cache County, Utah has water-quality measurements published by Utah DWQ, shown here as reported. Water clarity: 15.4 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Surface area: 297 acres.
Is Newton Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Newton Reservoir across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
127 measurements from 2 monitoring stations, 2014–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Utah Department Of Environmental Quality
UTAHDWQ_WQX127 samples · 2014–2021
Analytical methods
- Field Measurements
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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.