HomeMy WebLinkAboutOshkosh Waterworks Next Steps 07.28.2025
July 28, 2025
DIANE BARTLETT – CITY CLERK
OSHKOSH WATERWORKS
PO BOX 1130
OSHKOSH, WI 54902
SUBJECT: COMPLETION OF STANDARD MONITORING AND NEXT STEPS
Dear Diane Bartlett,
During 2024 and 2025, Oshkosh Waterworks completed two-consecutive, six-month rounds of standard lead and
copper sampling below the lead and copper action levels. The table below summarizes the results of this
monitoring:
Monitoring Period Lead 90th [µg/L] Copper 90th [µg/L]
July-Dec 2024 6.1 180
Jan-June 2025 7.5 160
Based on these results, and in accordance with section NR 809.547(4)(d) Wisconsin Administrative Code, your
water system has been moved to annual monitoring and will therefore be required to collect thirty (30) lead and
copper samples during the June 1-September 30, 2026 monitoring period.
Optimal Water Quality Parameters (OWQPs)
By December 19, 2025, the Department of Natural Resources (Department) will establish optimal water quality
parameters (OWQPs) which reflect optimal corrosion control treatment (OCCT) for your public water system in
accordance with s. NR 809.542(4)(f) Wis. Adm. Code. At a minimum, in accordance with s. NR 809.543(7) Wis.
Adm. Code, the Department will establish the following:
• A minimum value or range for pH at each entry point to the distribution system.
• A minimum pH value measured at all taps in the distribution system.
• A minimum concentration or a range of concentrations for the inhibitor, measured at each entry point to
the distribution system and in all tap samples.
Water suppliers are encouraged, but not required to recommend OWQPs for department consideration. If
Oshkosh Waterworks intends to recommend OWQPs, please notify the Department of your intent within
14 days of receiving this letter (August 11, 2025), and the department will then assign a deadline by which the
water system must submit their final recommendation.
The Department notes that in 2021, Oshkosh recommended entry point water parameter targets and ranges in their
Corrosion Control Treatment Study, but did not recommend distribution system OWQP values. If Oshkosh
Waterworks chooses to use the entry point ranges submitted in 2021 for their OWQP recommendation, additional
distribution system OWQP values must be specified.
State of Wisconsin
DEPARTMENT OF NATURAL RESOURCES
101 S. Webster Street
Box 7921
Madison WI 53707-7921
PWSID: 47104574
MUNICIPAL COMMUNITY
WINNEBAGO COUNTY
dnr.wi.gov
wisconsin.gov
In the 2021 Corrosion Control Treatment Study, Oshkosh Waterworks recommended the following water
quality parameter targets and ranges:
Entry Point Target and Range for pH
• Target pH = 7.4
• Acceptable pH range = 7.0 to 7.8
Entry Point Target and Range for Orthophosphate
• Target orthophosphate = 2.0 mg/L as PO4
• Acceptable orthophosphate range = 1.5 to 2.5 mg/L as PO4
The Department will notify Oshkosh Waterworks, in writing, of their assigned OWQPs by December 19, 2025,
and explain the basis for its determination [ss. NR 809.542(4)(f), NR 809.543(6), and NR 809.543(7) Wis. Adm.
Code]. In accordance with s. NR 809.542(4)(g) Wis. Adm. Code., the water system will be required to operate in
compliance with the department-approved OWQPs.
We appreciate your willingness to provide and maintain a safe public drinking water system. If you have any
questions regarding this letter or would like to setup a meeting to discuss anything, you may contact me at
Samuel.Munk@wisconsin.gov.
Sincerely,
Samuel Munk
Corrosion Control Specialist
Lead and Copper Section
Drinking Water and Groundwater Program
ECopy:
Brad Rokus – Water Plant Superintendent, Oshkosh Waterworks
Rebecca Grill – Oshkosh Waterworks
James Rabe – Oshkosh Waterworks
Jamie Douglas – Water Supply Engineer, DNR, Appleton
Skye Anne Tompkins – Lead and Copper Field Expert, DNR, Green Bay
JaNelle Merry – NR Supervisor, DNR, Green Bay
Sarah Gunnell – Lead and Copper Monitoring Specialist, DNR, Madison
Ann Hirekatur – Lead and Copper Section Manager, DNR, Madison