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Hayley Siltanen


555 17th Street, Suite 3200, Denver, CO 80202

Hayley Siltanen effectively assists clients in matters involving water rights, real estate, and land use planning.

Her clients include water providers, energy companies, real estate developers, industrial water users, ranchers and farmers, and special districts. Hayley has experience with a broad range of land use, natural resources, and environmental matters, including project permitting, administrative and judicial appeals, real property transactions, and environmental compliance.


Hayley assists clients in matters involving:

  • Water rights 
  • Energy project permitting
  • Land use

She also has experience assisting client on complex environmental issues arising under:

  • Clean Water Act (CWA)
  • Endangered Species Act (ESA)
  • Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
  • Resource Conservation and Recovery Act (RCRA)
  • Reclamation Act
  • Toxic Substances Control Act (TSCA)
  • Emergency Planning and Community Right-to-Know Act (EPCRA) 
  • Coastal Zone Management Act (CZMA)
  • Wild and Scenic Rivers Act

Client Results

  • Prior to joining Holland & Hart, Hayley practiced in California and Oregon, focusing on environmental and water law matters, including:

    • Represented water users before the Oregon Water Resources Department in matters concerning water right forfeiture, water right transfers, water storage and use applications, and applications for time extensions
    • Represented utility-scale solar and commercial developers in obtaining entitlements at the city and county level
    • Advised irrigation districts on election, public records, and other procedural matters



Bar Admissions


Unless you are a current client of Holland & Hart LLP, please do not send any confidential information by email. If you are not a current client and send an email to an individual at Holland & Hart LLP, you acknowledge that we have no obligation to maintain the confidentiality of any information you submit to us, unless we have already agreed to represent you or we later agree to do so. Thus, we may represent a party adverse to you, even if the information you submit to us could be used against you in a matter, and even if you submitted it in a good faith effort to retain us.