Stormwater Management

The City Engineer manages the City’s program to develop, implement and enforce a stormwater management program designed to reduce the discharge of pollutants to the maximum extent practicable to protect water quality. Stormwater runoff is generated when precipitation or snow melt flows over land or impervious surfaces and does not infiltrate into the ground. As the runoff flows over the land or impervious surfaces (paved streets, parking lots, sidewalks and building rooftops), it accumulates debris, chemicals, sediment, or other pollutants that could adversely affect water quality if the runoff is discharged untreated. The primary method to control stormwater discharges is the use of best management practices (BMPs). In addition, most stormwater discharges are considered point sources and require coverage under an NPDES/MS4 permit. 

Water pollution degrades surface waters making them unsafe for drinking, fishing, swimming, and other activities. Authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program for MS4 controls water pollution by regulating point sources that discharge pollutants into waters of the United States. Point sources are discrete conveyances such as pipes or man-made ditches. Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES/MS4 permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters. Since its introduction in 1972, the NPDES permit program is responsible for significant improvements to our Nation’s water quality. Communities with 1000 people or more per square mile must follow the NPDES General Permit for Small Municipal Separate Storm Sewer Systems (MS4). The City of Ontario became a small MS4 in 2009 and is required to maintain a small MS4 permit through the Ohio Environmental Protection Agency. These regulations require designated communities to develop and implement a storm water management plan (SWMP).

This is accomplished by implementing six minimum control measures (click on each of the 6). 

  1. Public Education and Outreach —
    BMPs for MS4s to inform individuals and households about ways to reduce stormwater pollution.
  2. Public Involvement and Participation —
    BMPs for MS4s to involve the public in the development, implementation, and review of an MS4’s stormwater management program.
  3. Illicit Discharge Detection & Elimination —
    BMPs for identifying and eliminating illicit discharges and spills to storm drain systems.
  4. Construction Runoff Control —
    BMPs for MS4s and construction site operators to address stormwater runoff from active construction sites.
  5. Post-construction Runoff Control —
    BMPs for MS4s, developers, and property owners to address stormwater runoff after construction activities have completed. 
  6. Pollution Prevention/Good Housekeeping —
    BMPs for MS4s to address stormwater runoff from their own facilities and activities.

Stormwater Control Measures Inspection Forms

Ohio’s maintenance standards and design specifications for Stormwater Control Measures (SCMs) can be found at Ohio SCM Inspection and Maintenance Manual

An updated list of certified contractors for SCM Inspection and Maintenance is maintained at the bottom of Inspection and Maintenance for SCMs Certification Program

Public Education and Outreach

Stormwater Theme 2026:

“Better Site design and maintenance: focusing of improving storm water components of site designs and the need for post-construction storm water management at both new development and redevelopment sites.”

Proper site design, maintenance and post-construction stormwater management are crucial for reducing pollution, preventing floods, and protecting water resources by integrating natural processes into developments to manage runoff at the source. If water quality impacts are considered from the beginning stages of a project, new development and potentially redevelopment provide more opportunities for water quality protection. EPA recommends that the SCMs chosen: be appropriate for the local community; minimize water quality impacts; and attempt to maintain pre-development runoff conditions.

Key Concepts in Better Site Design & Stormwater Management:

· Reduce Impervious Surfaces: Minimize concrete/asphalt by using permeable pavers, green roofs, or smaller footprints to let rain soak in.

· Manage Runoff Close to Source: Implement practices like rain gardens, bioswales (vegetated channels), and redirecting downspouts to vegetated areas.

· Protect Natural Features: Conserve streams, wetlands, and mature trees, as they naturally filter and slow water.

· Utilize Green Infrastructure: Employ Low Impact Development (LID) techniques that mimic natural water cycles, like rain barrels and bioretention cells.

Stormwater Management for New & Redevelopment Sites:

· New Development: Proactively design for stormwater, preventing pollution from the start rather than retrofitting later.

· Redevelopment: Offers a chance to fix existing problems and upgrade older sites with modern, effective stormwater controls.

· Environmental Protection: Prevents pollutants (trash, chemicals, sediment) from reaching water bodies.

· Flood Control & Water Supply: Reduces peak flows, preventing flooding and recharging groundwater.

Stormwater Management and Construction Stormwater Permitting:

To limit the negative impacts of construction projects and construction of impervious areas on Ohio’s waters, Ohio EPA administers a permitting program designed to document construction activity in the state and require practices that keep pollutants out of the streams during and after construction. The permitting program is mandated in the Clean Water Act and is part of the NPDES (National Pollutant Discharge Elimination System) program.

Ohio EPA and the City of Ontario work with developers, engineers and construction site operators to make sure they have the proper stormwater controls in place during construction and ensuring installation of the required post construction stormwater controls.

The OEPA NPDES permitting program and City of Ontario require the development and implementation of a Stormwater Pollution Prevention Plan (SWPPP) for construction sites. A SWPPP outlines the control, practices and policies that will be implemented to prevent stormwater pollution from construction activities as well as control for stormwater management following construction.

The City of Ontario has developed standards within Ontario Codified Ordinance for construction stormwater protection in Chapter 1353 Erosion and Sediment Control and for post construction stormwater management in Chapter 937 Stormwater Management (see link at the bottom of the page). The Rainwater and Land Development Manual defines Ohio’s standards and specifications for stormwater management practices implemented during land development and post construction stormwater management.

Stormwater Control Measure Long-Term Maintenance:

Effective post-construction programs ensure that Stormwater Control Measures (SCMs) function as intended over their multi-decade lifespans. Longterm Maintenance Plans are required for development and redevelopment as per Chapter 937 Stormwater Management within the City of Ontario. A Long-Term Maintenance Plan (LTMP) for Stormwater Control Measures (SCMs) ensures these systems (like rain gardens, ponds, swales) stay functional by detailing responsibilities, inspection schedules, maintenance tasks, and funding, typically prepared by the designer, recorded legally, and updated, to prevent failures and protect water quality, often mandated by local regulations. Key elements include system descriptions, “as-built” drawings, inspection checklists (see links above), vegetation needs, debris removal plans, and assigned personnel, with consequences for neglect often involving local government intervention at the owner’s cost.

Ohio’s inspection and maintenance standards for Stormwater Control Measures (SCMs) can be found at Ohio SCM Inspection and Maintenance Manual.

See the below resources for additional information on better site design and post construction stormwater management:

bmp-site-design-and-planning-strategies.pdf by EPA

2.0-Postconstruction-SW-Mgmt-Practices.pdf by OEPA

Public Involvement and Participation

Events page: https://ontarioohio.org/ontario-events/

Ontario Calendars

Illicit Discharge Detection and Elimination

Illicit Discharge Detection Flyer by Respect Our Waters
Chapter 938 Illicit Discharge and Connection Stormwater Regulation

Contact the City of Ontario to report
suspected illegal dumping or illicit discharge

Zoning Inspector
3375 Milligan Road, Ontario, Ohio 44906
Office: 419-529-2530
Cell: 419-961-7222
Zoning@ontarioohio.org

Construction and Post Construction Runoff

Chapter 937 Stormwater Management
Chapter 1353 Erosion and Sediment Control
Chapter 1354 Riparian and Wetland Setbacks
Ontario Codes and Ordinances

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