Purchasing Assistant (#RB0500)
$26.23-$31.89 Hourly / $4,547.31-$5,527.28 Monthly / $54,567.75-$66,327.44 Yearly


Under general supervision, learns to perform professional and analytical purchasing work for the procurement of supplies, materials, equipment, and services; and does related or other work as required in accordance with Rule 3, Section 3 of the Civil Service Rules.


This is the entry-level class in the professional purchasing series. An employee in this class is responsible for learning and performing volume purchasing functions such as review of requisitions, preparation of bid and proposal invitations, communication with vendor representatives, and development of County operating orders. Initially, employees work under close supervision, but as knowledge and proficiency increases, they assume greater independence and responsibility for the full scope of purchasing assignments.

Note for Purchasing Assistants assigned to operating departments: The Director of Purchasing and Support Services is the chief purchasing agent for the County. Purchasing Assistants assigned to operating departments must fully comply with all rules and regulations established by the Director for the acquisition of supplies, materials and equipment for their departments.


  • Assists in reviewing and analyzing requisitions from County departments for the purchase of supplies, materials, equipment, and services; confers with department customers regarding their procurement needs and learns to determine whether the items specified are best suited to meet those needs; learns to determine the most appropriate and economical method for the purchase of items and/or services.
  • Learns to prepare purchase orders to selected vendors and to check purchase orders for accuracy and compliance with specifications when competed; confers with supervisor and department representatives on possible alternate items; learns to approve and sign purchase orders.
  • Learns to prepare requests for bid, requests for proposals, and other types of bid invitations, learns to coordinate the solicitation of bids/proposals process and to conduct pre-bid, proposal, and other technical support meetings; learns to participate on evaluation panels for selection of contractors; consults as needed with the County Purchasing Agent, County Counsel, department heads, members of the Board of Supervisors, and others regarding the more complex or sensitive purchases.
  • Learns to analyze bids and proposals and ensure compliance with standards and requirements; learns to write contracts and other purchasing documents; learns to obtain required support documents and submit for approval.  
  • Confers with representatives of manufacturing and commercial firms regarding suitability, availability and prices of commodities; learns to negotiate cost, scope and purchasing standards; provides technical support and advice to contractors regarding San Joaquin County purchasing procedures.
  • Conducts surveys; compiles statistics on the annual consumption of certain products; prepares reports; maintains files and records.


Education: Graduation from an accredited college or university with a bachelor’s degree in public or business administration, political science, economics, or a related field.

Substitutions: 1) Possession of a valid certificate as a Certified Purchasing Manager (CPM) issued by the Institute of Supply Management, or a Certified Professional Public Buyer (CPPB) or Certified Public Procurement Officer (CPPO) issued by the Universal Public Procurement Certification Council (UPPCC), may be substituted for the above-required education; OR 2) purchasing experience that included reviewing requisitions, drafting specifications and bids, analyzing bids, and working with vendors and operating departments, may be substituted for the above-required education on a year-for-year basis.


The principles and practices of business administration; basic public purchasing practices and techniques; modern office practices and procedures.


Learn and apply the principles and practices used in the purchasing of commodities; apply sound judgement in the analysis of bids and specifications; establish and maintain effective working relations with a variety of individuals including operating departments and vendor representatives; express oneself, clearly and concisely, both orally and in writing.


San Joaquin County complies with the Americans with Disabilities Act (ADA) and, upon request, will consider reasonable accommodations to enable individuals with disabilities to perform essential job functions.

CLASS: RB0500; EST: 12/20/1973; REV: 5/10/2017;