Case Study

How Adams County, CO Simplifies MS4 Inspections with OpenGov Asset Management

To comply with state requirements under the U.S. Clean Water Act, municipalities spend weeks each year inspecting every outfall from their permitted Municipal Separate Stormwater Sewer Systems (MS4s) to search for illicit discharges or cross connections. Compliance can be perplexing as requirements vary from state to state, and often within states. However, some MS4 operators are finding ways to simplify the annual outfall inspection process with the help of government technology.


Agency Type

Annual Budget
USD 556,533,737.00



Asset Management

Customer Results

MS4 Inspections Automatically Integrated With Existing Records

Upgraded Overall Condition Index (OCI) Of Stormwater Assets

Paperless Project Tracking from Inspection to Repair


In Colorado, reporting requirements may sound straightforward: Phase II MS4 operators just need to verify that all of their outfalls are inspected annually during dry weather. Reports may range from a simple statement of the number of inspections completed to a detailed map showing hundreds of inspection sites.

However, stormwater departments must be prepared with more detail than the total number of MS4 outfall inspections. If a polluted discharge is discovered and corrected, documentation of field test results and enforcement actions may be required. Or the state may decide to conduct an audit or request a specific report.

For many MS4 operators, such as Adams County, Colorado, this means mounds of paperwork. After about two weeks of field inspections, Adams County staff spends almost as much time compiling and entering or scanning spreadsheets, photos, and other paper documentation, says Juliana Archuleta, stormwater administrator for the county. “If you want to go back and look at the previous year, you have to pull the old documents and manually go through them,” she says.


Adams County has been using Cartegraph for 5 years, but only recently configured it for MS4 use. Not every Adams County’s storm sewer asset is located within the MS4 permitted area so, “We added a checkbox to our outlet assets indicating whether it’s in the MS4 Permit Area,” explains GIS analyst Charles Osterman. “This makes it easy to pull a list and create MS4 inspection tasks for only the required outfalls.”

The software will also simplify the field inspection process. Instead of walking around and trying to identify outfalls by matching them up with maps and GPS coordinates, inspectors can use Esri maps within Cartegraph to guide them directly to the asset.
While Adams County will conduct its MS4 inspections in Cartegraph for the first time this fall, the engineering team in Castle Rock, Colorado, has been using Cartegraph to inspect its 150 stormwater basins and other MS4 assets for three years.

Matt Daniels, utilities mapping specialist and asset program manager, configured the electronic inspection form in Cartegraph based on the stormwater operation’s existing MS4 paper form. Using the familiar format ensured that the procedure would be easy to learn and would capture the needed information.


MS4 inspection findings are automatically integrated with existing asset records, making it easy to query and share data, and even assign tasks when inspectors find conditions needing repair or maintenance. For example, if a clogged outfall is discovered, with the push of a button the highway crew can be assigned to clean it out. There’s no need to route paperwork or coordinate departments. Even though it involves different work teams, Cartegraph can track all steps of the task for that asset from the inspection to the repair.

This capability has helped Castle Rock upgrade the Overall Condition Index (OCI) of its stormwater assets. “Our MS4 inspection has 64 categories,” says Daniels. “Everything on the form is set up according to condition categories.”

Back in Adams County, Archuleta is eager to use the system’s automated record-keeping and reporting. “I can query on any field and report on what we did,” she says. “For example: show me all the [MS4 outfalls] that had flow compared to the ones that didn’t during the dry weather inspection.” Whatever information the state may ask for, the system puts it at her fingertips.

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