Typical pollutants found in stormwater collected from different source areas Typical pollutants found in stormwater collected from different source areas

Typical pollutants found in stormwater collected from different source areas

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Source Area	Solids	Total suspended solids	Nutrients	Bacteria	Metals	Chloride	Grease, Oil	Pesticides	Other chemicals
Hard Roofs1	○		○	○	●				○
Green and Brown Roofs2		○	○	○					○
Paved Surfaces (parking lots, sidewalks, driveways and roadways)	○	●	○	○	○	●	●		○
Green Spaces (lawns and park areas)	○	○	○	●				●	○

● = relatively high concentrations
○ = relatively low concentrations
¹Metals are highly dependent on roof type-only certified membrane roofs are currently approved for potable through NSF.
²Vegetated roofs and pervious pavers have had poor performance due to discoloration of water and difficulty filtering the water to levels that the UV treatment is effective.