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Interest rates

The Clean Water Fund Program (CWFP) and Safe Drinking Water Loan Program (SDWLP) fund eligible projects with 20-year loans at below-market interest rates from 0.00% to 1.485%.

Interest rate determination

This table shows determination of the loan interest rate by project type, based on the current market rate.
Clean Water Fund Program (CWFP)
For the portion of eligible projects for receiving and storing septage, and capacity for treating septage; as well as for mercury remediation at wastewater treatment facilities.
0% 0% 0%
For eligible projects of extremely disadvantaged municipalities meeting the following financial need criteria:
  • < 1,000 population; and
  • ≤ 65% of Wisconsin Median Household Income (MHI).
0% 0% 0%
CWFP and Safe Drinking Water Loan Program (SDWLP)
For eligible projects of disadvantaged municipalities meeting the following financial need criteria:
  • < 10,000 population; and
  • ≤ 80% of Wisconsin Median Household Income (MHI).
33% 0.891% 0.957%
For eligible projects of municipalities not meeting the financial need criteria.
55% 1.485% 1.595%
MARKET RATE (effective 07/01/2021 thru 09/30/2021) 100% 2.700% 2.900%

Between July 1, 2021 and September 30, 2021, the market rate for loans up to and equal to 20 years is 2.70% and the market rate for loans exceeding 20 years is 2.90%.

Competitive market rate

On a quarterly basis, the Wisconsin Department of Administration (DOA) assesses the market rate on which the program subsidies are based. The rate applied to the loan is the market rate in effect at the time of the municipal bond meeting (at which resolutions approving municipal obligations and Financial Assistance Agreements (FAAs) are signed/executed).


The CWFP and SDWLP provide subsidy to bring interest rates on loans down from the market rate established by DOA to the reduced interest rates described in the table shown above. Municipalities may receive loans at or below the market rate for publicly-owned drinking water, wastewater, and storm water infrastructure projects.

Some municipalities may also be eligible for additional subsidy in the form of principal forgiveness (PF). PF is comparable to a grant because it reduces the size of the loan, thus reducing annual principal and interest payments. The PF allocation methodology is structured to allocate PF funds to the highest priority projects of municipalities with the greatest financial need. Principal forgiveness policies are described in the annual Intended Use Plans (IUPs).

Fixed interest rates on long-term loans

Loan terms are typically 20 years. Loan terms up to 30 years are available for projects that submit documentation supporting a useful life of 20+ years and in which the DNR concurs with that useful life determination. The loan terms cannot be greater than the useful life of the project. Sewer pipe projects are assumed to have a useful life of 30+ years, and therefore, are exempt from the additional documentation requirement. The interest rate for loans with terms greater than 20 years will be determined by the DOA at the time of loan closing and are expected to be slightly higher than the rate for 20-year loans.

Authority and laws

Most eligible project costs are funded at a percentage of the market interest rate, in accordance with ss. 281.58(12) and 281.61(11), Wis. Stats., and ss. NR 162.11 and 166.13, Wis. Adm. Code.

The interest rate for the portion of a project that provides facilities for receiving and storing septage and capacity for treating septage is zero percent, in accordance with s. 281.58(12)(a)5., Wis. Stats.

If the DNR determines that a portion of a scored project is ineligible, it shall specifically identify the ineligible portions and the associated costs; or prorate the amount of financial assistance to reflect the appropriate proportion of eligible to ineligible project costs; or both.

Contact information
For information on this topic, contact:
DOA Capital Finance Office staff at

Disclaimer of guidance: This document is intended solely as guidance and does not contain any mandatory requirements except where requirements found in statute or administrative rule are referenced. Any regulatory decisions made by the Department of Natural Resources in any matter addressed by this guidance will be made by applying the governing statutes and administrative rules to the relevant facts. Program implementation details are outlined in the governing administrative codes and statutes: §§ 281.58 and 281.59 and 281.61, Wis. Stat., and chs. NR 162 and 166, Wis. Adm. Code.