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Senior Mechanical Engineer

Willdan Group, Inc.
Walnut, CA Full Time
POSTED ON 6/21/2026
AVAILABLE BEFORE 8/20/2026

Willdan Performance Engineering, a subsidiary of Willdan, is seeking a Senior Mechanical Engineer in Walnut, CA.

Summary

This position is critical to maintaining operational continuity, supporting organizational growth, and ensuring the delivery of high-quality engineering services that exceed client expectations. Having extensive practical experience in mechanical engineering is important to effectively provide day-to-day operational, technical, and project leadership. The Senior Mechanical Engineer will be responsible for managing engineering staff, supporting business pursuits, overseeing design delivery within budget, and ensuring quality assurance/quality control (QA/QC) standards are met across projects. The Senior Mechanical Engineer must be able to manage multiple priorities in a fast-paced environment and serve as the Mechanical Engineer of Record.

Essential Duties and Responsibilities

  • Manage daily operations of the WES Industrial Engineering Department.
  • Coordinate workloads, staffing assignments, and resource planning to support on-time project delivery.
  • Provide guidance, technical support, and mentorship to engineers and designers.
  • Perform project technical reviews to ensure compliance with applicable codes, standards, and client requirements.
  • Resolve complex technical challenges and design coordination issues.
  • Support troubleshooting and system optimization efforts.
  • Provide senior-level engineering oversight for mechanical, plumbing, and controls design projects.
  • Work with and manage a multi-disciplinary subconsultant team of electrical engineers, civil engineers, structural engineers, architects, and other disciplines as required for projects.
  • Perform site assessments (as needed) and coordinate with clients, contractors, and regulatory agencies.
  • Assist with construction administration support including RFIs, submittals, and field coordination.
  • Support staff development, training, and performance improvement initiatives.
  • Foster a collaborative and accountable team environment.
  • Enforce internal QA/QC procedures and technical standards.
  • Perform peer reviews and final design quality checks prior to issuance.
  • Maintain engineering standards, templates, and best practices.
  • Assist with project scope development, fee estimating, staffing plans, schedule development, and risk assessments.
  • Prepare technical narratives.
  • Support presentations and technical interviews as needed.
  • Must be proficient in AutoCAD / Revit / BIM platforms, Energy modeling and engineering analysis tools, and Microsoft Office Suite.

Job Requirements / Qualifications:

  • Bachelor's degree in mechanical engineering (master's degree is preferrable).
  • Active California Professional Engineer License (other States a plus) with no pending adverse actions.
  • Possess NCEES Record.
  • Demonstrated experience in consulting engineering and multidisciplinary project delivery.
  • Minimum of 10 to 15 years of senior engineering design experience.
  • Experience with data centers and process cooling and heating systems controls or central plant systems, along with associated plumbing design.
  • Familiarity with QA/QC programs and technical standards implementation.
  • Prior leadership, mentoring, and supervisory experience.
  • Experience writing proposals and supporting business development efforts.
  • Travel may be required depending on project needs.
  • Essential Competencies
    • Design and Development
    • Strong Analytical Skills
    • Technical Leadership
    • Technical Documentation
    • Troubleshooting
    • Organization and Project Management
    • Communication
    • Interdisciplinary Collaboration
    • Client Liaison

EEO Non-Discrimination and ADA Reasonable Accommodation Statement
Willdan is an equal opportunity employer. Applicants are considered for all positions without regard to race, religious creed, color, age marital status, sex, sexual orientation, gender identity, gender expression, citizenship status, national origin, ancestry, religion, military service or veteran status, disability, medical condition, childbirth and related medical conditions, genetic testing, reproductive status or any other classification protected by federal, state or local laws and ordinances. Willdan does not discriminate on the basis of physical or mental disability where the essential functions of the job can be reasonably accommodated. Determinations on requests for reasonable accommodation will be made on a case-by-case basis. If you need reasonable accommodation for any part of the application and hiring process, please notify us.

Willdan Energy Solutions participates in E-Verify.

 

Salary.com Estimation for Senior Mechanical Engineer in Walnut, CA
$175,585 to $211,462
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