RSA+ is a consulting civil engineering and surveying company serving Northern California for 35+ years. Formerly known as Riechers Spence & Associates, we specialize in Land Planning, Engineering and Surveying for Residential Subdivisions, Resorts + Hotels, Commercial + Industrial Developments, Wineries + Vineyards, Public Improvements, Estate Residential, Wastewater Systems and more.

We take pride in the fact that we approach projects from both an innovative and practical perspective. We keep pace with changing conditions and regulations as well as new technologies. We are a team of innovators and leaders and we customize preparation of our plans and specifications to meet requirements and facilitate a timely, successful review.

With our established company infrastructure, breadth of experience, wide-ranging capabilities, innovative philosophy and our personal approach to business, we stand ready and able to provide consulting services that will address your project's challenges. Through our quality of work and client service, our goal is to leave an indelible impression of a positive experience and make you a return client.

RSA+ Leaders

Hugh Linn, President
Ryan Gregory, Vice President
Christopher Tibbits, Vice President



  • Hanna Court, American Canyon
  • Kendall-Jackson | Biagi Brothers
  • Oxbow District
  • The Napa Riverfront (Multi Use Development), Napa
  • St. Helena Purlieu | Cairdean Estate (Multi Use Development), St. Helena

Estate Residential

  • Sage Canyon Residence, Napa County
  • Lake County Residence
  • Soda Canyon Residence, Napa County
  • Atlas Peak Residence, City of Napa
  • Rutherford Hill Residence, Napa County
  • Silverado Trail Residence, Napa County

Healthcare | Institutional

  • Queen of the Valley Hospital, Napa
  • Napa Valley Unified School District, Napa
  • St. Helena Montessori School, St. Helena


  • Grizzly Island Bike Trail, Suisun City
  • Highway 29 | Imola Avenue Signalization, City of Napa
  • Pope Street Realignment, City of St. Helena
  • Wappo Park | Pope Street Multipurpose Trail, City of St. Helena
  • Yountville Mile Class | Bike Lane, Town of Yountville
  • Yountville Street Light Replacement, Town of Yountville
  • Bus Shelter, Town of Yountville
  • North Yountville Bike Route, Town of Yountville
  • Napa Valley Vine Trail - Napa to Yountville Initial Study, County of Napa
  • Napa County Secure Staff Facility, County of Napa
  • Devlin Road Extension, County of Napa
  • Soscol Gateway Transit Center, Napa County Transportation & Planning Agency
  • Napa Valley Vine Trail - Oak Knoll Section, Napa County Transportation & Planning Agency
  • Howell Mountain Water Tanks, Howell Mountain Mutual Water Company
  • Fairway Path Extension, City of Calistoga


  • Eagle Vines Golf Club, Napa
  • North Bay BMX Track, Napa
  • St. Helena Skatepark, St. Helena
  • City of Napa: Opera House Plaza, Napa

Resort | Hotel

  • Meritage | Vino Bello Resorts, Napa
  • Westin Verasa, Napa
  • Avia Hotel, Napa
  • Archer Hotel, Napa


  • Continuum Winery, St. Helena
  • Black Stallion Winery, Napa
  • Sage Hill Winery, St. Helena
  • Quintessa Winery, St. Helena
  • Ovid Winery, Napa County
  • Napa Valley Vintners, St. Helena
  • B Cellars
  • Cairdean Winery
  • Kenzo Winery
  • Honig Winery - Left Turn Lane

Residential Subdivision

  • Dry Creek Road Subdivision, Napa
  • Saratoga Subdivision, Napa
  • Chesapeake Village, Napa
  • Hidden Hills Subdivision, Napa
  • Montrachet Apartments, Napa
  • Pear Tree Lane Subdivision, Napa
  • The Ranch Subdivision, Fairfield
  • Chalk Ridge Subdivision, Windsor