Last Updated 08/24/2026
Great Falls Stormwater Regulations
Excerpt: MCM5 Post-Construction Site Storm Water Management in New and Redevelopment
Post-Construction is an essential part to water quality because it is the finished product after construction. It is important that the systems set in place are functioning properly and maintained to design specifications. The MS4 permit has specific language on how to achieve compliance with MCM-5, the most current City of Great Falls Storm Drainage Design Manual and there are also local ordinances in Title 17 Chapter 52 of the Official Code of the City of Great Falls and are summarized below:
- Applies to any property that has or will have 15000 sq ft of impervious surface.
- All private stormwater treatment practices/facilities shall have an enforceable operation and maintenance agreement with the City and other applicable parties to ensure the system functions properly as per 17.52.100.
17.52.100 – Maintenance Agreements
A. General. All private stormwater treatment practices/facilities shall have an enforceable operation and maintenance agreement with the City and other applicable parties to ensure the system functions properly.
B. Contents of agreement. This agreement shall at a minimum include the following provisions:
- The agreement shall run with the land and is binding on all property owners served by the practice/facility.
- The agreement includes an easement, as may be required, to access and inspect the practice/facility, and to perform work as necessary to ensure the system functions properly.
- The agreement shall include a long-term maintenance schedule and specifications to ensure the system functions properly.
- A qualified individual shall inspect the practice/facility on an annual basis to document maintenance and repair needs and ensure compliance with the requirements of this chapter.
- Any maintenance needs found must be addressed in a timely manner.
- The agreement grants the Director of Public Works the right of physical access to the practice/facility for periodic inspections and corrective actions as may be appropriate.
- If the practice/facility serves more than one (1) parcel, the agreement shall have a formal mechanism for sharing in the cost of maintenance.
- Copies of all reports/inspections shall be submitted to the Director of Public Works within ten (10) days of completion.
- The Director of Public Works may impose additional requirements to ensure the practice/facility functions properly.
- Failure to meet the terms of the agreement constitutes a violation of the land development code.
- The agreement can only be terminated with written approval of the Director of Public Works when the practice/facility is no longer needed.
- The responsible party shall keep a copy of all reports and maintenance records for a period of ten (10) years.
C. Recordation. The agreement, as approved by the Director of Public Works, shall be recorded in the official records of the County Clerk and Recorder.
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Frequently Asked Questions
What size property triggers post-construction stormwater requirements in Great Falls?
The city’s post-construction standards under MCM5 apply to any property that has, or will have, 15,000 square feet of impervious surface. Properties at or above that threshold need an enforceable operation and maintenance agreement with the city for any private stormwater treatment practice or facility.
What has to be included in a Great Falls stormwater maintenance agreement?
At minimum, the agreement must run with the land and bind all current and future property owners served by the facility, include an easement for access and inspection, and set out a long-term maintenance schedule. It must also name a qualified individual to inspect the facility annually, document maintenance and repair needs, and grant the Director of Public Works physical access for periodic inspections and corrective action.
What happens if a Great Falls stormwater facility serves more than one property?
The maintenance agreement must include a formal mechanism for sharing the cost of maintenance among all the parcels the facility serves. This keeps upkeep from falling entirely on one owner when a shared pond, swale, or other BMP benefits multiple properties.
How long does a Great Falls property owner need to keep stormwater maintenance records?
Records and inspection reports must be retained for 10 years. Copies of each inspection or report also have to be submitted to the Director of Public Works within 10 days of completion, and any maintenance needs identified must be addressed in a timely manner.
Can a Great Falls stormwater maintenance agreement be terminated?
Only with written approval from the Director of Public Works, and only once the facility is no longer needed. The agreement itself must be recorded in the official records of the County Clerk and Recorder, so it stays tied to the property regardless of ownership changes.
What happens if a Great Falls property owner doesn't meet the terms of their maintenance agreement?
Failing to meet the agreement’s terms is treated as a violation of the city’s land development code. The Director of Public Works also retains authority to impose additional requirements on a facility if needed to ensure it continues functioning properly.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
