Grafton Millpond
Ozaukee County, Wisconsin35 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Grafton Millpond. Here is what has been measured.
- Public access
- Limited data
Grafton Millpond in Ozaukee County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Phosphorus: 110 µg/L. Surface area: 35 acres.
Grafton Millpond is a 35-acre lake in Ozaukee County, Wisconsin. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-08-12. Methodology: how these readings are compared.
What Grafton Millpond is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grafton Millpond 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 Grafton Millpond
These are the measurements Wisconsin DNR publishes for Grafton Millpond, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 110 µg/L. TSI 72.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 110µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| 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. | 72 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Grafton Millpond
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
35 acres
Public access
Yes
Listed by Wisconsin DNR
No bathymetric survey has been published for Grafton Millpond, so its depth is not documented here.
Recreation & Access
- GraftonPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fishing Grafton Millpond
Reservoir Info (USACE NID)
Grafton Millpond is a man-made reservoir impounded by the Grafton (completed 1918), built primarily for recreation on the MILWAUKEE; buttress-type dam, 20 ft tall and 206 ft long.
- Surface area
- 35 ac
- Normal storage
- 260 ac-ft
- Max storage
- 400 ac-ft
- Drainage area
- 451 sq mi
- Hazard class
- Significant
- Owner
- Village Of Grafton
Source: USACE National Inventory of Dams, NID ID WI00171 · Operator website · Matched by proximity (0.23 km)
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Grafton Millpond under Clean Water Act (NPDES) discharge permits, including 2 classified by the EPA as major dischargers. 2 facilities have a reported Clean Water Act violation in the past three years.
- Grafton Village Water & Wastewater UtilityGrafton · 1.4 mi away · NPDES WI0020184MajorRecent violation
- Cedarburg City WwtfCedarburg · 2.6 mi away · NPDES WI0020222MajorRecent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Ozaukee County
Frequently asked questions about Grafton Millpond
Where is Grafton Millpond?
- Grafton Millpond is a lake in Ozaukee County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Grafton Millpond?
- Grafton Millpond in Ozaukee County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Phosphorus: 110 µg/L. Surface area: 35 acres.
Is Grafton Millpond safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Grafton Millpond?
- Grafton Millpond has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Grafton. Public access is listed as yes.
Can I fish at Grafton Millpond?
- Grafton Millpond has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
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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)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory