Mary Piasta

Mary Piasta

mary-piastaPresident & Owner

Adept at navigating thorny issues ranging from real estate to the complexities of estate planning, Mary Piasta’s proactive legal counsel provides peace of mind to entrepreneurs, family-owned businesses, and individuals. She advises on critical business decisions and the transition of leadership and inheritance across generations. Mary’s clients include diverse businesses of all sizes, ranging from solos and start-ups to t  multi-generational wineries, and vineyard management companies.

Full Spectrum Legal Counsel
Drawing on her own multi-generational trajectory and community ties, Mary offers individuals, families, and businesses full spectrum advice to accomplish their goals. From building a business to assessing real estate holdings and maximizing wealth for future generations, she consistently finds innovative solutions to protect her clients’ business interests and personal concerns. Mary’s counsel helps sustain family business across generations and also charts a clear path for entrepreneurs just starting to create their own legacies.

Focus on Legacy
Continuing a family legacy, Mary follows in the footsteps of her father, Colonel Joseph A. Piasta II. His strengths as a leading attorney, experienced trial lawyer, and zealous advocate inform Mary’s practice. Combining a passion for law with a deep-rooted commitment to the ties of family, Mary adeptly navigates the intricacies of family-owned businesses and multi-generational family estates to resolve legal tangles, sort out complex real estate issues, and alleviate the legal complexities of family ties. Whether you are just starting a family or already have a seat at a crowded ancestral table, Mary provides savvy counsel ranging from advising on wealth management and business strategies to supporting the unfaltering commitment of family business to the communities they call home.

Estate Planning Advice and Counsel
Mary speaks candidly to individuals and families about how she can provide them with peace of mind about their legal concerns for life and beyond. Combining legal skills with a compassionate outlook, her toolkit includes powers of attorney and healthcare directives for the living and wills, trusts, and related planning structures. She has seen firsthand how messy things can get when a loved one dies, and aims to alleviate this concern for her clients. As she puts it, “We are the legal architects for our clients as they progress through life to ensure that their plans match their goals as circumstances shift and change over time.” The firm’s services  include:

  • Charitable interest trusts
  • Defective grantor trusts
  • Grantor retained annuity trusts
  • Irrevocable trusts
  • Irrevocable life insurance trusts
  • Special needs trusts
  • Tax planning trusts

Comprehensive Real Estate Counsel
Mary provides a full range of real estate services to clients over a wide range of asset types, Her comprehensive knowledge of local real estate markets gives her clients an edge across a full range of transactional processes and regulatory issues. Mary counsels throughout the transaction process, negotiating ownership transfers and contractual arrangements including leases. She handles disclosure analysis, advises on landlord-tenant issues for commercial and residential real estate, structures real estate ownership interests, and other ventures. No matter what the issue, Mary has the legal experience and/or will build the team to meet her clients’ needs.

Business-Savvy with Litigation Strengths
Business-savvy to the core, Mary also pilots businesses through the economic uncertainties, including dissolutions and other necessary transitions. With in-depth legal knowledge honed by thirteen years of complex litigation, including the top California real estate jury verdict of 2014, Mary resolves tough legal problems with an ease born of practice. She remains on the cutting edge of situations, most recently aligned with two other Sonoma Valley professionals to address pandemic-related legal, finance, and real estate issues in the Sonoma Brain Trust webinar series.

Before HVP
An alum of the Governor Gray Davis administration, Mary aided the First Lady, organizing visits throughout the state to showcase the diversity of community culture, elected officials, schools, and businesses. During law school, she clerked at Cotchette, Pitre & McCarthy. In her spare time, she lobbied successfully for policies affecting the rights of children at the UN Women’s Commission. She went on to a successful career at several large Bay Area law firms, before returning to her roots to become the first woman partner at the venerable firm of Haeuser, Valluzzo & Piasta LLP.

Community Focused
Passionate about preserving Sonoma’s history, buildings, and culture, Mary has most recently served on the board of the Sonoma Valley League for Historic Preservation. Committed to children’s issues locally and internationally, she has been on the boards of the Kenwood Education Foundation and the Ama Foundation. She has also served on the Sonoma Community Service and Environment Commission as well as the board of the Sonoma Valley Mother’s Club.

Life Beyond the Firm
Mary feels blessed to call Sonoma Valley home, where she lives with her husband, two sons and daughter, rescue pup, and pet tortoise.


  • University of San Francisco School of Law, J.D., 2003
  • University of California, Davis, B.A., 1993

Awards and Accolades
Mary was the first lawyer to be named a Sonoma Star by Valley of the Moon Magazine, naming her one in 2018, preceded by North Bay Business Journal’s selecting her One to Watch in 2017.

Presentations and Publications
In addition to her Sonoma Brain Trust video series, the firm newsletter and frequent blog posts, Mary has recently presented or authored the following: