EXHIBIT 8.1


October 22, 2004

Headwaters Incorporated
10653 South River Front Parkway
Suite 300
South Jordan, UT 84095

Ladies and Gentlemen:

         We have acted as counsel to Headwaters Incorporated, a Delaware
corporation (the "Company"), in connection with the preparation and filing by
the Company with the Securities and Exchange Commission of the Registration
Statement on Form S-3 filed July 19, 2004 (the "Registration Statement") under
the Securities Act of 1933, as amended (the "Securities Act"), with respect to
the registration of (i) $172,500,000 in aggregate principal amount of 27/8%
Convertible Subordinated Notes due 2016 (the "Notes") issued pursuant to the
terms of an indenture dated as of June 1, 2004, between the Company and Wells
Fargo Bank, N.A., as trustee and (ii) an aggregate of 5,750,000 shares of
Company common stock, $0.001 par value, initially issuable upon conversion of
the Notes.

         We are of the opinion that the statements set forth in the Registration
Statement under the caption "Material United States Federal Income Tax
Considerations," insofar as those statements purport to constitute summaries of
matters of United States federal tax law and regulations or legal conclusions
with respect thereto, constitute accurate summaries of the matters described
therein in all material respects.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the use of our name therein. In giving such
consent, we do not thereby admit that we are within the category of persons
whose consent is required under Section 7 of the Securities Act.

Very truly yours,

/s/PillsburyWinthropLLP