Rainbow Lake
Vilas County, Wisconsin148 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Rainbow Lake. Here is what has been measured.
- Mesotrophic
- 36 ft max depth
- Limited data
Rainbow Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 13.1 µg/L. Maximum depth: 36 ft. Surface area: 148 acres.
Wisconsin DNR lists Walleye as common on Rainbow Lake. DNR survey details →
Rainbow Lake is a 148-acre mesotrophic lake in Vilas County, Wisconsin with a maximum depth of 36 feet. Water clarity is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Compared to the 102 other monitored lakes in Vilas County, Rainbow Lake ranks #20 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-22. Methodology: how these readings are compared.
What Rainbow Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
- Deep water36 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
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 Rainbow Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Rainbow Lake
These are the measurements Wisconsin DNR publishes for Rainbow Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6 ft. Phosphorus 13.1 µg/L. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13.1µg/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. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Rainbow Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Rainbow Lake typically sits around 72°F at the surface in August. Summer average is about 69°F. Usually warmest in Jul (about 72°F) and coldest in Apr (about 47°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (47°F) to its warmest (72°F).
Typical surface water temperature by month, from 10 field readings (2024–2025) via the EPA Water Quality Portal. See the full Rainbow Lake water temperature breakdown →
Wisconsin DNR lists Walleye as common on Rainbow Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Rainbow Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2005. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
36 ft
Surface area
148 acres
Lake Size & Watershed
Watershed (drainage) area
0 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.7 mi
HydroLAKES / HydroSHEDS
Elevation
1,621 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Rainbow Lake
Compare lakeside cabins, hotels, and vacation rentals near Rainbow Lake in Vilas County, Wisconsin — 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 Rainbow Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Rainbow Lake
Water Quality Trend: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Improving6 years
Phosphorus
Worsening+0.38 µg/L/yr7 years
Nearby Lakes in Vilas County
Frequently asked questions about Rainbow Lake
Where is Rainbow Lake?
- Rainbow Lake is a lake in Vilas County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Rainbow Lake?
- Rainbow Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 13.1 µg/L. Maximum depth: 36 ft. Surface area: 148 acres.
Is Rainbow Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Rainbow Lake?
- Rainbow Lake typically sits around 72°F at the surface in August, from 10 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Rainbow Lake?
- Rainbow Lake has a maximum depth of 36 feet. The lake covers 148 acres.
What fish are in Rainbow Lake?
- Fish species found in Rainbow Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Rainbow Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Rainbow Lake?
- Wisconsin DNR lists Walleye as common on Rainbow Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Rainbow Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Explore Rainbow Lake across LakeQuality
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Where this data comes from
65 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX65 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes