Lake Merrywater
Lake Merrywater in Hillsborough County, Florida has a water quality grade of B (Good). Water clarity: 3.9 ft visibility. Phosphorus: 18 µg/L.
- Clarity
- 3.9 ft
- Typical in August
- 86°F
- Type
- Eutrophic
- Trend
- ↑ Improving
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Lake Merrywater is a productive, nutrient-rich eutrophic lake in Hillsborough County, Florida. Water quality is graded B based on 1 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 123 other monitored lakes in Hillsborough County, Lake Merrywater ranks #73 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2024-08-21. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Murky, only visible to about 3.9 ft. Phosphorus level: 18 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.9 ft | Not graded |
| Phosphorus | 18 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lake Merrywater
Compare lakeside cabins, hotels, and vacation rentals near Lake Merrywater in Hillsborough County, Florida — 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 Lake Merrywater
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Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Lake Merrywater typically sits around 86°F at the surface in August. Summer average is about 86°F. Usually warmest in Aug (about 86°F) and coldest in Jan (about 59°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 83 field readings (2010–2024) via the EPA Water Quality Portal. See the full Lake Merrywater water temperature breakdown →
Fishing Lake Merrywater
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.225 m/yr | 5 |
| Phosphorus | → Stable | +0.2 µg/L/yr | 5 |
EPA Impairment Status
Lake Merrywater is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit FL1478H · Official waterbody report · Matched by proximity (0.88 km)
County Ranking
Ranked #73 of 124 lakes in Hillsborough County
Nearby Lakes in Hillsborough County
Frequently asked questions about Lake Merrywater
Where is Lake Merrywater?
- Lake Merrywater is a lake in Hillsborough County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Merrywater?
- Lake Merrywater in Hillsborough County, Florida has a water quality grade of B (Good). Water clarity: 3.9 ft visibility. Phosphorus: 18 µg/L.
Is Lake Merrywater safe to swim in?
- Good for swimming, clear water with low algae levels. Lake Merrywater has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Lake Merrywater?
- Lake Merrywater typically sits around 86°F at the surface in August, from 83 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
Explore Lake Merrywater across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Eutrophic Lakes in Florida
Where this data comes from
30 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples30 samples · 2020–2024
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database