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LakeQuality

Grafton Millpond vs Thiensville Millpond

Water quality, depth, fish species, and recreation comparison.

Grafton Millpond and Thiensville Millpond both received the same overall water quality grade of F (Very Poor). Both are in Ozaukee County, Wisconsin.

Both Grafton Millpond and Thiensville Millpond sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. These two are within a letter of each other on the rubric — Grafton Millpond (F) versus Thiensville Millpond (F). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.

With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.

F

Grafton Millpond

Ozaukee County, Wisconsin

No clarity data.

F

Thiensville Millpond

Ozaukee County, Wisconsin

No clarity data.

Side-by-Side Metrics

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

MetricGrafton MillpondThiensville Millpond
Overall GradeF (Very Poor)F (Very Poor)
Water ClarityNo dataNo data
Phosphorus110 µg/L166 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth--
Surface Area35 acres45 acres
Public AccessUnknownUnknown
Fish Species00
Trophic Statehypereutrophichypereutrophic

Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).

Verdict

Both lakes earn the same Grade F. The tiebreakers come down to what you want from the lake. Grafton Millpond matches its peer on species count.