OECM Clients supported by OECM agreements are located in the following nine (9) Zones as set out below.

Zone 1 - The Counties of Elgin, Essex, Lambton, and Middlesex and the Municipality of Chatham-Kent;
Zone 2 - The Counties of Bruce, Dufferin, Grey, Huron, Perth, Simcoe, and Wellington;
Zone 3 - The Counties of Brant, Haldimand, Norfolk, and Oxford, the Regional Municipalities of Halton, Niagara, and Waterloo, and the City of Hamilton;
Zone 4 - The City of Toronto and the Regional Municipalities of Durham, Peel, and York;
Zone 5 - The Counties of Haliburton, Hastings, Lennox and Addington, Northumberland, Peterborough, and Prince Edward, the District Municipality of Muskoka, and the City of Kawartha Lakes;
Zone 6 - The Counties of Frontenac, Lanark and Renfrew, the United Counties of Leeds and Grenville, Prescott and Russell, Stormont, Dundas and Glengarry, and the City of Ottawa;
Zone 7 - The Districts of Algoma, Manitoulin, Nipissing, Parry Sound, and Sudbury and the City of Greater Sudbury;
Zone 8 - The Districts of Cochrane and Timiskaming, and;
Zone 9 - The Districts of Kenora, Rainy River, and Thunder Bay and areas lying outside the boundaries of the province of Ontario