HC Storm Water District Regulations

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Rules and Regulations Of The Hamilton County Storm Water District
Issued By The Board Of County Commissioners
Hamilton County, Ohio

Effective September 12, 2019


The Hamilton County Storm Water District was established in response to the federally mandated National Pollutant Discharge Elimination System (NPDES) Phase II Storm Water Program.  

In addition to the unincorporated Township areas of Hamilton County,
Planning + Development is the Regulating Authority for selected
Municipalities in Hamilton County as of June 14, 2009

Click here to view this Municipality list.

Submit all construction drawings to Planning + Development
for storm water Quality and Quantity review and approval.

Article I - Definitions  

Article V - Post Construction Storm Water Quality Regulations  

Water Quality Plan Review Checklist  

Article IV Stream Corridor Regulations

Downspout Regulations

Storm Water Drainage System (SDS) Rules And Regulations

For buildings on developed lots, as in subdivisions, etc., adequate surface grading, building drains and/or sewer-connected drains shall be provided. This grading, and the drains where necessary, shall be shown on the survey/site plan of the building permit plans. The Hamilton County Building Commissioner is responsible for obtaining this plan prior to issuing any building permit. Requirements for out letting of downspouts are included in Section 206 of the Hamilton County Engineers Subdivision Manual ("Rules and Regulations of the Office of the Hamilton County Engineer Governing Surface Public Improvements for Private Developments within the Unincorporated Areas of Hamilton County, Ohio") dated January 1, 2001 (or as subsequently revised). Downspout outlets shall comply with these Rules and Regulations as well as the Rules and Regulations of the Plumbing Division of the Hamilton County Board of Health and the Building Commissioner of Hamilton County. Developers are advised that when downspouts are discharged to the rear (or side) of a proposed lot, that flow should not be directed toward another building, or to a subdivision lot where a building is likely to be constructed, which would create storm water problems for such building.

The Hamilton County Director of Public Works is not responsible for review of plans for downspout outlets, or the issuance of permits for such. The review and approval shall be obtained from the office of the Hamilton County Engineer and the office of the Plumbing Division or the Hamilton County Board of Health.

Section ST 302  

County Engineer Regulations (Effective - April 1, 2006 - Section 206)

Building downspout pipe outlets should be installed in the following order of priority:
1. To rear of proposed lot.
2. By connection to a collector pipe installed parallel to the street curb. See Standard Drawing No.4 and 8.
3. To nearest storm sewer inlet or storm manhole.
4. By approved connection to a storm sewer (one 6 " connection per lot).
5. To the nearest drainage course, i.e. natural swale or existing ditch.

Except for extremely unusual cases as determined by the Hamilton County Engineer, after written request by the developer, no downspouts shall be outletted through curb cuts.

In NO case shall downspout effluent be permitted to flow across sidewalks or drive aprons.


Building Commission Regulations (Section B5 Grading and Drainage)

3. Positive surface drainage shall be provided for each lot so there is no unplanned pocketing of water on any surface. Downspout and sump pump storm water discharge, when piped below ground, shall be dispersed onto the ground surface no closer than ten (10) feet to adjoining properties.

Flood Regulations

Planning + Development staff will review all development plans for compliance with the Hamilton County Flood Damage Prevention Regulations by determining if the development is located within a Special Flood Hazard Area (SFHA) 100-year floodplain. Hamilton County adopted these rules as a requirement to the National Flood Insurance Program (NFIP) administered by the Federal Emergency Management Agency (FEMA).

NFIP provides maps of the 100-year floodplain and the regulatory requirements for Hamilton County’s floodplain management program. It is also the primary provider of insurance against flood damage (regular homeowner insurance does not cover this). Flood insurance is mandatory for all structures within a FEMA-regulated Special Flood Hazard Area.

The Planning and Development staff reviews all development plans for all unincorporated Hamilton County Townships, ONLY. All villages, cities or other municipalities not within the unincorporated areas of Hamilton County must contact that particular municipality for floodplain information/requirements for that jurisdiction.

Contact Olivia Maltry, Floodplain Technician at (513) 946-4760 or [email protected]  

Flood Damage Prevention Regulations   (HCFDPR)

Flood Damage Prevention Regulations - Commissioner Approval   (12/16/21)

SDS Regulations

Hamilton County Planning + Development
Storm Water Drainage System (SDS) Rules And Regulations Governing The Design, Construction, Operation, Maintenance, And Use In The County Of Hamilton Storm Drainage System
Effective January 17, 2007
By The Board Of Hamilton County Commissioners

Click here for a summary of the changes to our Regulations