You likely think about stormwater compliance during active construction. It’s also important to plan for the stormwater features that remain in place once a site is stabilized. Under Colorado’s Municipal Separate Storm Sewer System (MS4) permits for post-construction stormwater control, permittees are required to maintain written procedures for the long-term operation and maintenance of structural control measures. The State of Colorado also issues a separate permit—CDPS General Permit COR0900000—which authorizes regulated stormwater discharges from MS4 systems owned or operated by local government entities. While the COR0900000 permit requires at least one inspection of structural control measures during the permit term, most Colorado MS4 programs go further and require these features to be inspected annually to ensure they continue functioning as designed.
Who’s Responsible?
During construction, the developer or contractor is responsible for inspections under the COR400000 Construction Stormwater Discharge Permit. Once the site becomes stabilized and permanent features are installed, the responsibility typically shifts to the property owner, HOA, or local jurisdiction, depending on the development agreement. Because ownership often transfers after construction, it is common for new owners to be unaware that they have inherited stormwater facilities. This often leads to an overlook of the inspection requirements tied to them—making clarity in responsibility a critical aspect of long-term compliance.
Annual Inspections vs. Routine Inspections
Annual stormwater compliance inspections are just as important as routine active construction stormwater inspections under the CDPS COR400000 Construction Stormwater Discharge Permit. During active construction, inspections are required at least bi-weekly with post-storm inspections for all construction projects that disturb over an acre of land or are part of a larger plan of development. If any permanent structural Control Measures (CMs) are installed, the CDPS COR0900000 must be obtained. Cities like Denver require annual inspections of these features. Colorado Springs mandates that private BMP owners submit a completed inspection and maintenance report each year and maintain documentation for several years. Various municipal requirements exist across the state of Colorado.
An annual inspection typically evaluates whether a permanent stormwater control measure is operating as intended. Inspectors review the structural integrity of the feature, look for sediment buildup, assess the condition of inlets and outlets, examine vegetation growth or encroachment, check for erosion and standing water, and verify that the BMP matches its approved design or O&M manual. After the inspection, the inspector prepares a detailed report that summarizes the condition of the BMP and notes any required maintenance. If problems are identified, the permittee must perform corrective actions in a timely manner. Additionally, many MS4s require that these reports be submitted directly to the municipality or kept on file for audit purposes.
Why Annual Inspections Matter
Once active construction is complete, the installed stormwater measures are often assumed to be functioning and are not frequently checked. Annual inspections often reveal issues that might otherwise go unnoticed, such as clogged outlet structures, excessive sediment accumulation, deteriorated vegetation, ponding water in infiltration systems, trash or debris buildup, erosion damage, or changes in drainage patterns. Identifying these issues early helps prevent failures, reduce repair costs, and maintain the long-term health of the stormwater system. Because stormwater controls are designed to last decades, even moderate neglect can lead to expensive rehabilitation or reconstruction.
Annual inspections matter because they protect both the permittee and the stormwater infrastructure. They ensure long-term performance, reduce liability, prevent costly repairs, and support compliance with local MS4 programs and state requirements. Perhaps most importantly, they help maintain the water quality and drainage standards that these systems were designed to achieve.
Preparing for an Annual Inspection
Preparing for an annual stormwater inspection is simple but valuable. Property owners benefit from gathering past inspection records, ensuring access to all BMPs, removing vegetation or debris that may obstruct inspection areas, reviewing previous corrective actions, and sharing any site changes or updates with the inspector. This preparation helps ensure that the inspection is accurate, efficient, and fully reflective of current site conditions.
Working with a professional inspector is one of the most effective ways to stay compliant. A qualified stormwater consultant brings experience with state and municipal requirements, understands the technical aspects of BMP design and function, and provides thorough documentation that can be relied upon during audits or enforcement reviews. Professional inspectors offer objective assessments, identify deficiencies early, and provide clear recommendations for maintenance or repairs, all of which help property owners avoid compliance issues and protect their long-term investment.
Ready to Schedule Your Annual Inspection?
Summit Services Group supports owners, developers, and municipalities across Colorado by providing comprehensive annual inspections for permanent stormwater control measures. Our team delivers detailed reports with photographs, clear recommendations, and practical guidance for corrective actions. We maintain thorough documentation for recordkeeping requirements and help clients navigate the expectations of their local MS4 program. Whether you manage a single pond or an entire development, we ensure your stormwater facilities continue to function as designed.
If you’re ready to schedule your annual stormwater inspection or need help understanding your MS4 requirements, Summit Services Group is here to help. Contact us today to get your inspection on the calendar and keep your project compliant year after year.