By Shannon Madden
In a highly urban environment like northeast Illinois, we’re used to managing stormwater by sending it down the drain as fast as possible with gutters, pipes, and pavement. But since we pay to capture, convey, and treat all water that enters combined sewer systems (and we pay for the first two with separate sewer systems as well), that conventional approach is costly and wastes a valuable resource. What we need is a mental shift away from directing stormwater off our property to actually valuing rain as a resource. The POLIS Water Sustainability Project at the University of Victoria calls for this transition from “stormwater cities” to “rainwater cities” in Peeling Back the Pavement: Reinventing Rainwater Management in Canada’s Communities.
Here’s a thought exercise: Let’s say two neighbors both enjoy gardening. Neighbor 1 waters her garden from the tap for an hour each morning, while Neighbor 2’s hose connects to a rain barrel filled with water from his roof. If both neighbors pay the city for their water use, who do you think is getting a better deal?
And what if those neighbors aren’t just two gardeners, but entire towns that pay for their public water supply?
I’m sure you see where this is going. POLIS might consider Neighbor 1 a “stormwater city,” or an area that relies on costly, treated water for almost all of its water needs, while simply sending away the resource that lands on our roofs and parking lots. Neighbor 2, on the other hand, is the savvy consumer that wouldn’t dream of paying for tap water to nourish his garden until he’d used that valuable rainwater first.
Let’s think a bit more. What do we need to make this shift? Do we need incentives for homeowners and developers? New laws that allow rainwater to be used for purposes other than drinking water? How about regional planning that transcends jurisdictions? The POLIS article reminds us that we need each of these critical factors. The great news is that they’re all becoming a reality in our region.
Incentives like the Illinois Green Infrastructure Grant provide resources for everyone from first-time homeowners to the Chicago Department of Transportation to be smart, sustainable neighbors who integrate urban development into the natural water cycle. Green infrastructure incorporates natural elements, like rain gardens, into the urban landscape. This slows the flow of water into our sewers, reduces long-term infrastructure maintenance needs and water treatment costs, and helps us make ecological and efficient use of the resource that falls from the sky.
Laws are being revised, too. The Metropolitan Planning Council and the Illinois Department of Public Health are working to modify the Illinois Plumbing Code to set standards for non-potable uses of rainwater, like filling toilets. Not only will this help Illinoisans reduce our water bills, but it’s also been found to be profitable for developers in places like Oregon, where laws already allow for expanded uses of rainwater.
Regional planning is also under way. We all know that water ignores our political boundaries. Case in point, the Fox River passes through 10 communities in Wisconsin and another 24 towns in Illinois! That’s why we can’t manage water resources in one jurisdiction at a time. Instead, as the POLIS article points out, we need to make watershed-level and regional decisions as we learn to develop within the natural hydrological cycle. The Chicago Metropolitan Agency for Planning set an important local precedent by leading 11 counties in developing WATER 2050: Northeastern Illinois Water Supply/Demand Plan. The Northwest Water Planning Alliance is another positive collaboration of roughly 80 communities working to manage their shared groundwater resource. Check out this video of a Canadian example, the Bowker Creek Intiative.
Just as POLIS encourages Canadians to use rainwater as a valuable urban resource, Americans must also make this shift. Using rainwater for non-potable purposes, instead of sending it straight to the sewer system, makes economic and ecological sense. It’s time to change our attitude toward rainwater to show just how much we value it.
What levels of contaminants does rainwater in an urban environment have versus the levels in treated water that comes from the tap? This question is inspired by your two neighborhood thought exercise where the collected water would nourish a lawn rather than flush a toilet. A related question: How would a community (whether it be household or city) filter contaminants and debris entrained in water from rooftops, parking lots, other runoff surfaces, etc.? If this is even a need…?
Great questions! The level of contaminants in rainwater depends on what the rainwater hits before it gets to your green infrastructure. If it’s going straight from the sky or a gutter into a rain barrel, there shouldn’t really be any contaminants (other than debris) and can be directly used for watering lawns. If it comes from a parking lot or street that could pick up oil or other substances off the pavement, then there could be contaminants. Different green infrastructure practices are used for different things. Permeable pavements and bioswales are meant to eventually allow the water to infiltrate into the ground, which depending on the soils, will give it time to filter out contaminants on its way into the ground (chlorides, like road salt, are a notable exception to this). Green roofs and rain gardens tend to use plants that are tolerant to salt and other contaminants, and some plants even help filter things out of the water as they soak. If rainwater is going to be reused in the home for toilets or other nonpotable uses, there are relatively simple filtering systems that can be installed to clean up that water.