Storm drains and pipes that collect stormwater and transfer this runoff to local waterways are gray infrastructure. In contrast, green infrastructure utilizes natural plantings and structures to capture, absorb, filter and/or reuse stormwater.

Princeton now has several stormwater management ordinances designed to mitigate the stormwater impacts of new developments and redevelopment. Planning to add a garage or expand your kitchen? Additions of 400 square feet or more are required to implement select green infrastructure measures to store and manage the runoff created by this new impervious surface. Learn more with the Municipality’s infographic.

• Rain gardens utilize a shallow depression filled with native plants to capture and filter stormwater, providing beauty and encouraging wildlife. Learn to design your own rain garden from The Rain Garden Manual of New Jersey and/or the Rain Garden Manual for New Jersey. UConn’s Rain Garden app is another helpful tool to design and build a rain garden.
• Bioswales are similar to rain gardens, but also move water away from buildings to better locations for absorption. 
• Downspout planters are plant boxes installed at the base of a gutter downspout. They capture water for reuse while showcasing your flowers.  Review our instructions for building a downspout planter as well as our installation instructions.
• Stormwater planters and tree filter boxes are a type of basin built into a sidewalk to capture stormwater runoff from the road or sidewalk.
• Rain barrels or cisterns capture rainfall, typically from a roof. This water can then be reused for watering gardens or washing vehicles. Check out Rutger’s fact sheet on How to Build a Rain Barrel.
• Permeable pavement allows water to quickly pass through the pavement to an underlying layer that allows storage until it is fully absorbed. This includes porous asphalt, pervious concrete, and interlocking pavers.
• Dry well systems utilize underground containers to accept large volumes of stormwater, allowing it to slowly seep into the ground.

Want to learn more? Check out Rutger’s New Jersey Green Infrastructure Guidance Manual to learn more about each of these options.

Eager to see demonstration projects and learn who and how they were built? The Watershed Institute’s Green Infrastructure Atlas highlights numerous projects in Princeton and Hopewell, including rain gardens, green roofs, downspout planters, and more.

Interested in learning where our water comes from, what happens to it as it runs through town, and where it goes? Check out Princeton’s Water Story. Once you’ve done this, have fun playing with the Global River Runner to map the path a rain drop takes, anywhere in the world!

• Rain, rain, go away. In 2018, Mercer County experienced the highest annual precipitation ever recorded; a developing trend.
• We’ve paved paradise. Our driveways, roads, parking lots, rooftops and sidewalks add up. Currently, 14% of  Princeton’s landscape is impervious, or unable to effectively absorb rainfall.
• A dangerous combination. Increased impervious landscape combined with heavier rains leads to more flooded homes and blocked roadways.