Hillsborough-Rainbow Lake
Hillsborough County, FloridaView mapDirections
Florida DEP publishes the water-quality measurements for Hillsborough-Rainbow Lake. Here is what has been measured.
- Mesotrophic
- Limited data
Hillsborough-Rainbow Lake in Hillsborough County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 16 µg/L.
Hillsborough-Rainbow Lake is a mesotrophic lake in Hillsborough County, Florida. Water clarity is declining over recent sampling years. Compared to the 123 other monitored lakes in Hillsborough County, Hillsborough-Rainbow Lake ranks #59 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2021-10-31. Methodology: how these readings are compared.
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 Hillsborough-Rainbow Lake is safe to swim in today is a call for the Florida Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Hillsborough-Rainbow Lake
These are the measurements Florida DEP publishes for Hillsborough-Rainbow Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 8 ft. Phosphorus 16 µg/L. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 16µg/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 Hillsborough-Rainbow Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Hillsborough-Rainbow Lake typically sits around 78°F at the surface in October. Summer average is about 87°F. Usually warmest in Jun (about 88°F) and coldest in Dec (about 55°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (55°F) to its warmest (88°F).
Typical surface water temperature by month, from 124 field readings (2010–2017) via the EPA Water Quality Portal. See the full Hillsborough-Rainbow Lake water temperature breakdown →
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Stays near Hillsborough-Rainbow Lake
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Fishing Hillsborough-Rainbow Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Improving-0.57 µg/L/yr6 years
Nearby Lakes in Hillsborough County
Frequently asked questions about Hillsborough-Rainbow Lake
Where is Hillsborough-Rainbow Lake?
- Hillsborough-Rainbow Lake is a lake in Hillsborough County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Hillsborough-Rainbow Lake?
- Hillsborough-Rainbow Lake in Hillsborough County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 16 µg/L.
Is Hillsborough-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 Hillsborough-Rainbow Lake?
- Hillsborough-Rainbow Lake typically sits around 78°F at the surface in October, from 124 EPA Water Quality Portal field readings (2010–2017). That is a typical value for the month, not a live reading.
Explore Hillsborough-Rainbow Lake across LakeQuality
More lakes in Florida
Other Lakes in Florida
Mesotrophic Lakes in Florida
Where this data comes from
11 measurements from 3 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX11 samples · 2021
Monitoring station identifiers (3)
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.