Thiensville Millpond
Thiensville Millpond in Ozaukee County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 166 µg/L. Surface area: 45 acres.
- Area
- 45 acres
- Public access
- Yes
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Why Thiensville Millpond has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Thiensville Millpond, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded phosphorus, but not water clarity and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Thiensville Millpond is a 45-acre lake in Ozaukee County, Wisconsin. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-08-19. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Thiensville Millpond
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Phosphorus level: 166 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 166 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Thiensville Millpond
Compare lakeside cabins, hotels, and vacation rentals near Thiensville Millpond in Ozaukee 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.
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 45 acres |
| Public Access | Yes |
No bathymetric survey has been published for Thiensville Millpond, so its depth is not documented here.
Recreation & Access
- ThiensvillePublic
- Village Grove ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Thiensville Millpond
Reservoir Info (USACE NID)
Thiensville Millpond is a man-made reservoir impounded by the Thiensville (completed 1842), built primarily for recreation on the MILWAUKEE; gravity-type dam, 13 ft tall and 370 ft long.
- Surface area
- 45 ac
- Normal storage
- 700 ac-ft
- Max storage
- 2,200 ac-ft
- Drainage area
- 594 sq mi
- Hazard class
- Low
- Owner
- City of Mequon
Source: USACE National Inventory of Dams, NID ID WI00539 · Operator website · Matched by proximity (0.09 km)
Graded lakes near Thiensville Millpond
Thiensville Millpond has no grade, but these lakes within a short drive do.
Nearby Lakes in Ozaukee County
Frequently asked questions about Thiensville Millpond
Where is Thiensville Millpond?
- Thiensville Millpond is a lake in Ozaukee County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Thiensville Millpond?
- Thiensville Millpond in Ozaukee County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 166 µg/L. Surface area: 45 acres.
Is Thiensville Millpond safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Thiensville Millpond is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Are there boat ramps on Thiensville Millpond?
- Thiensville Millpond has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Thiensville, Village Grove Park. Public access is listed as yes.
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Where this data comes from
1 measurement from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX1 sample · 2024
Analytical methods
- Phosphorus by Colorimetry
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
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory