Procurement Documentation / Definitions

To provide guidance and definition of the different acquisition methods and documents used by Washtenaw County in procurement of all goods and services.


The type of Purchase Order processed is determined by the type of commodity or service required and the term or period the purchase will be made. Types of orders and necessary documents are listed below with their particular criteria for usage.

  • Purchase Order: Normally processed for all purchases of material, equipment or service.
  • Blanket Orders / Price Agreements: A Purchase Order normally processed where material or equipment will be used on a frequent or repetitive schedule. This order normally covers an annual period for specific items at unit prices.
  • Service Contracts/Maintenance Contracts: Used for any services/maintenance the County needs. A contract must be in place and a Purchase Order issued prior to any services provided. These contracts are typically established for a period of one to five years in duration. All contracts require proof of insurance by the vendor for the amounts stated by the County; Workers compensation as required by the Laws for the State of Michigan, and comprehensive general liability and automotive liability in an amount as required by the County.
  • Construction Contracts: Similar to a Service / Maintenance Contracts. Construction contracts usually define a specific task or certain construction that, when completed, signal the conclusion of the contract. Insurance requirements are necessary as well. These Contracts often require bonding and prevailing wage instead of living wage.
  • Change Orders: Used as supplements to any construction contract. Changes are requested by the using Departments and specify price changes, specification changes, shipping charges, delivery charges, installation, payment term changes, etc. Only the Purchasing Division has authority to modify a Purchase Order. If a contractor complies with an agency's request to alter a contract or purchase order without formal authorization from the Purchasing Division, the contractor may not be entitled to payment for the modified performance.
  • Professional Service Contracts: Used for the acquisition of professional services such as consultants, doctors, lawyers, nurses, architects, engineers, accountants, etc. Depending on the type of service required or the liability incurred, sufficient insurance limits may be required to cover items such as malpractice, etc., before a Purchase Order can be issued. Professional Liability insurance is required.


All contracts should clearly define the costs to be paid to the contractor as well as the RFP Number indicated. Additionally, a total amount or expenditure, (such as a "not to exceed" amount), and a specific hourly rate should also be included. Pricing information in sufficient detail must be provided in the contract document before a Purchase Order can be issued. If applicable, a complete schedule of labor charges may be required of the contractor.