You can’t manage what you haven’t inventoried. That sounds obvious, but it’s the problem behind nearly every stormwater program I’ve encountered at Colorado special districts: there’s no reliable record of what facilities the district owns, where they are, what condition they’re in, or when they were last inspected. The knowledge lives in the head of one long-tenured engineer or scattered across a decade of project files.
Building a proper asset inventory is the single most valuable thing a special district can do to get its stormwater program on solid footing. Everything else depends on having an accurate picture of what you own: inspection scheduling, capital forecasting, board reporting, regulatory documentation.
Here’s how to build one that will actually serve you.
Start With What Already Exists
Before anyone sets foot on site, pull together the documentary record. For most special districts, this means:
Drainage reports and as-builts. Every development within your district boundary that triggered a stormwater facility requirement should have a drainage report on file with the approving municipality or the district itself. These reports describe the facilities, their design specifications, and the ongoing maintenance requirements. If you don’t have copies, request them from the municipality. They’re public records.
Plat documents and easements. Stormwater facilities are typically shown on recorded plats and covered by drainage easements. These documents establish who owns the facility and who is responsible for maintaining it. For district-maintained facilities, this is the legal foundation of your maintenance obligation.
Operations and maintenance manuals. Some developments include a specific O&M manual for the stormwater facilities as a condition of approval. If one exists, it’s the most direct statement of what you’re required to do.
The goal of this phase is a list of known facilities, not yet a field-verified inventory. You’re establishing what the records say exists. Field work comes next.
Get Eyes on Every Asset
Once you have a list of known facilities, verify each one in the field. This doesn’t have to be a formal inspection. It’s reconnaissance. You’re confirming that the facility exists where the records say it is, getting a general sense of its condition, and capturing a baseline photo set.
For each facility, record:
Location. GPS coordinates are essential. A text description alone (“southeast corner of Filing 4”) becomes ambiguous the moment the person who wrote it leaves the district. A coordinate-based location can be found by anyone, years from now, without institutional knowledge.
Facility type. Detention pond, extended detention basin, bioretention cell, underground detention system, sand filter, outlet structure. The type determines the applicable maintenance requirements and lifecycle profile.
Physical characteristics. For ponds: approximate surface area, estimated depth, outlet structure type and size. For underground systems: pipe diameter, material, chamber type, and connection points. For water quality features: footprint area, soil media type if known. You don’t need survey-quality measurements at this stage. You need enough information to distinguish one asset from another and make reasonable maintenance decisions.
Approximate age and installed condition. The install date or approximate year of construction. If you don’t know the exact date, the plat recording date is a reasonable proxy. Age drives lifecycle projections, so even an estimate is better than nothing.
Current condition rating. A simple 1–5 scale (excellent, good, fair, poor, critical) is enough for an initial inventory. You’re not doing a full inspection at this stage. You’re getting a rough sense of where each asset sits on the spectrum between “functioning as designed” and “needs immediate attention.”
Photos. Photograph every asset from consistent angles: overall site, outlet structure, inlet area, embankment (for ponds), and any visible deficiencies. Date-stamped photos with GPS metadata create a baseline you can compare against in future inspections. They also provide legal documentation that the district knew the condition of the facility at a given point in time.
Organize by District Geography
Most special districts cover multiple sub-areas, filings, or phases developed at different times. Organizing your inventory to reflect this geography pays off when you need to answer questions like: “Which facilities are in Filing 6?” or “What stormwater assets are we taking on when we annex the Riverside development?”
A flat list of assets is workable for a district with ten facilities. For a district with sixty, you need a structure that groups assets by location, filing, or watershed so you can navigate and filter without scrolling through everything.
Identify the Gaps
After fieldwork, compare what you found against what the records say should exist. Some facilities will appear in the records but not in the field, typically because they were never built, were removed, or were redesigned during construction and the records weren’t updated. Some facilities will appear in the field but not in the records, common in older districts where documentation practices were inconsistent.
For facilities that appear in records but can’t be located in the field, dig deeper before writing them off. Check aerial imagery from multiple time periods. Talk to staff who’ve been with the district a long time. Contact the municipality. Sometimes these assets are there but not where the records suggest.
For facilities found in the field that aren’t in your records, confirm who owns them. Not every pond you find is the district’s responsibility. Some are owned by the municipality. Some belong to an HOA. Some are private. Clarify ownership before adding anything to your inventory, because adding an asset to your program implicitly accepts maintenance responsibility.
Keep It Current
An inventory built today and never updated is obsolete within a few years. New facilities come online as development continues. Conditions change as assets age. Ownership questions get resolved. Staff turns over and institutional knowledge is lost.
The inventory stays useful only if it’s connected to your ongoing inspection program. Every inspection should update the condition rating of the inspected asset and note any changes since the last visit. New assets should be added to the inventory before they’re accepted from a developer. Not after.
This is one of the core problems that DistrictWorks addresses. It’s built to hold your asset inventory alongside your inspection records, so the two stay synchronized. When you log an inspection, the asset record updates automatically. When you add a new asset, the capital forecast adjusts. The inventory isn’t a separate document that has to be maintained in parallel with everything else. It’s the foundation the entire program runs on.
What You Get on the Other Side
A complete, field-verified asset inventory with current condition ratings, location data, and a photo baseline gives your district several things it probably doesn’t have today: a defensible record of what you own and what condition it’s in, a foundation for capital forecasting that’s grounded in real asset data rather than guesswork, and a basis for inspection scheduling that prioritizes assets by condition and criticality rather than simply doing whatever’s in front of you.
It also gives your board something they can actually work with at a governance level: a clear picture of the district’s infrastructure obligations, what it will cost to meet them, and what happens if maintenance is deferred. That clarity is the difference between a stormwater program that runs on institutional knowledge and hope versus one that runs on documented information and a plan.
The work of building an inventory is front-loaded. Once it’s done, keeping it current is manageable. And the alternative is the kind of thing that looks fine until it isn’t: continuing to manage facilities you haven’t formally inventoried.