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Type of Inventory Information to Collect


It is necessary to collect attribute information about assets included in the inventory. There are any number of categories of information that can be collected about assets, so systems must think through what will be useful and what will not. A system should consider these types of questions when developing the inventory:

In collecting attribute information about assets, the system must determine what data will be useful and collect it. Oftentimes, it is tempting to collect all there is to collect. But it is neither possible nor cost-effective to collect every piece of data that could be collected on an asset. How much data and what type of data to collect on the assets should be determined based on a consideration of the following:

  • How will the data be used?
  • What data is important to upper management/elected officials/decision makers?
  • What resources are available to collect the data?
  • How much does it cost to collect the data?
  • When will the data be collected?
  • Can the quantity and type of attribute data be maintained over time?
  • Can the accuracy and quality of the data be ensured?

Keep in mind that the amount of data collected can be adjusted over time; attributes can be added and removed. However, it is best to give careful consideration to the data you want to collect at the very beginning.

When considering what data to collect about the assets, it is important to keep in mind that each asset category may need unique data sets. Examples of the types of information a system may want to collect about their assets is provided in the table below and is broken out by asset category type in the References Guides listed in the resources. There are many places a system can look to collect data about the assets. Once the types of information to collect have been identified, the data must be organized in an asset inventory.

Table 1: Possible Types of Data to Collect

Asset ID Number
Installation Date and Restoration Date(s)
Operational Status
(O=Operational, S= Standby, I= Inoperable)
Energy User Y/N
(If yes, add additional energy information)
Expiration Date of Warranty
Maintenance Details or Management Details
(type of maintenance completed, how the land area is managed)
Facility Name
If there is redundancy for this asset
Asset Class or Category
(Diameter, Length, Area, Volume, Treatment Capacity)
Model/Serial Number
Remaining Useful Life
Initial Cost
Supplier Name and Contact Info
Maintenance Frequency or Maintenance Rating
(5 = Regular Maintenance, 4 = Infrequent Maintenance, 3 = Rarely Maintained, 2 = Little to No Maintenance, 1 = Currently Needs Maintenance)
Asset function and/or how it provided Level of Service
Unique asset attributes
(color, direction to turn to operate, etc.)
System Notes/Comments
Sub Asset Class or Subcategory
Asset Ownership
Estimated Replacement Cost (in today's dollars)
Under Warranty (Y or N)
Who funds maintenance
If land area has a protected status (Wilderness Area, National Park, National Forest, State Park) or if the area is Environmentally Sensitive or other important information about the land
If Design Specification are Followed
Natural Assets may include additional information such as volume of water stored, average length, width, and depth, average flow rate, watershed name

Note: The items in bold text are necessary for every asset. The remaining items are optional.

For systems that are just getting started with data collection, it is important to implement a plan for what data to collect and how to go about collecting it, thinking about what will be useful now and in the future.  There are a number of systematic approaches to collecting the data needed for the asset inventory.

  • Collect data one type of asset at a time
  • Collect data on one portion of the system at a time (e.g., pretreatment, then treatment, then solids handling, then green infrastructure)
  • Collect the data by location within the system from one side to the other
  • Collect newer assets first
  • Collect the data based on year of installation or based on major construction projects (this approach could be based on as-built drawings)

When an inventory is first created, it is highly likely that there will be gaps in the data. During the initial inventory process, care should be taken to ensure that the best data possible is put into the inventory and reasonable estimates can be made for items that are missing. Collect the best and highest quality data given the available resources of personnel, time, records, and technology during the initial survey. Then allow data quality to improve later. The sophistication of the asset inventory can be increased over time. The system may start out with a simple approach and improve upon that as additional resources become available.

Ultimately, the asset inventory should support operational, management, and business analysis functions. The asset data should be relevant, useful, and manageable.

You do not want everything in your inventory – Stacy Gallick, Asset Management Director, Johnson County Wastewater, Olathe, KS                          

Deciding what to include in the inventory based on monetary value – Ted Riehle, Chief Operator, Old Forge Wastewater Treatment Plant, Old Forge, NY

Your natural instinct will be to collect too much data – Ross Waugh, Waugh Infrastructure Management, Timaru, NZ                                                                    

Start by collecting data on assets you can find easily – Bill Boulanger, Superintendent Public Works and Utilities, Community Service Division, City of Dover, NH