Folsom Lake
Placer County, California11,180 acresView mapDirections
SWRCB publishes the water-quality measurements for Folsom Lake. Here is what has been measured.
- Oligotrophic
- Public access
Folsom Lake in Placer County, California has water-quality measurements published by SWRCB, shown here as reported. Phosphorus: 5.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 11180 acres.
Folsom Lake is a 11,180-acre cold, clear oligotrophic lake in Placer County, California. Limited fish-species data available. Public access is available with 6 public boat landings.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-08-07. Methodology: how these readings are compared.
What Folsom Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch6 documented ramps
- Camping2 public campgrounds nearby
- Big water11,180 acres
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 Folsom Lake is safe to swim in today is a call for the California State Water Resources Control Board and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Folsom Lake
These are the measurements SWRCB publishes for Folsom Lake, 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 5.5 µg/L. Chlorophyll-a 1.6 µg/L. TSI 28.
| 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 | 5.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.6µg/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. | 28 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Folsom Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
11,180 acres
Public access
Yes
Listed by SWRCB
No bathymetric survey has been published for Folsom Lake, so its depth is not documented here.
Recreation & Access
- Folsom Lake State Recreation AreaPublic
- Folsom Lake MarinaPublic
- Folsom Lake State Recreation Area (Brown's Ravine)Public
- Folsom Lake State Recreation Area (Beal's Point)Public
- Folsom Lake State Recreation Area (Granite Bay)Public
- Folsom Lake Yacht ClubSemi-private
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Folsom Lake
- Folsom Lake State Recreational Area Folsom Lake Campground2.8 km
- Folsom Lake State Recreation Area Beals Point Campground3.0 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Folsom Lake
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Fishing Folsom Lake
Reservoir Info (USACE NID)
Folsom Lake is a man-made reservoir impounded by the Folsom Dike 4 (completed 1956), built primarily for flood risk reduction on the American River; earth-type dam, 30 ft tall and 1,420 ft long.
- Surface area
- 11,180 ac
- Max storage
- 976,955 ac-ft
- Drainage area
- 1,570 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
All listed purposes: Flood Risk Reduction;Irrigation;Recreation;Hydroelectric;Water Supply.
Source: USACE National Inventory of Dams, NID ID CA10148 · Operator website
Nearby Lakes in Placer County
Frequently asked questions about Folsom Lake
Where is Folsom Lake?
- Folsom Lake is a lake in Placer County, California. Its water-quality measurements are published by SWRCB and shown on this page as reported.
What is the water quality of Folsom Lake?
- Folsom Lake in Placer County, California has water-quality measurements published by SWRCB, shown here as reported. Phosphorus: 5.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 11180 acres.
Is Folsom Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Folsom Lake?
- Folsom Lake has 6 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Folsom Lake State Recreation Area, Folsom Lake Marina, Folsom Lake State Recreation Area (Brown's Ravine), Folsom Lake State Recreation Area (Beal's Point), among others. Public access is listed as yes.
Can I fish at Folsom Lake?
- Folsom Lake has 6 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by California's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Folsom Lake?
- Folsom Lake has 2 public campgrounds from USGS The National Map within 5 km, including Folsom Lake State Recreational Area Folsom Lake Campground, Folsom Lake State Recreation Area Beals Point Campground. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
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Where this data comes from
4 measurements from 2 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- USGS California Water Science Center
USGS-CA4 samples · 2023
Analytical methods
- Nutrients, wu, persulfate, color
- Pigments, algae, EPA445.0 w/ACTN
Monitoring station identifiers (2)
- USGS-384255121074201
- USGS-384420121091101
- CEDEN-514ELD051
- CEDEN-514L17008
- CEDEN-514PFL177
- CEDEN-514PLA050
- CEDEN-514PLA052
- CEDEN-514PLA053
- CEDEN-514PLA054
- CEDEN-514PLA055
- CEDEN-514PLA056
- CEDEN-514PLA105
- CEDEN-514PLA106
- CEDEN-514SAC013
- CEDEN-514ST0498
- NALMS-F223648
- NARS_WQX-NLA_CA-10114
- USGS-384357121063601
- USGS-384521121074101
- USGS-384524121040101
- USGS-384857121054301
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
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles