A “Rain Tax” that Rewards Stormwater Harvesting is a Good Idea

Here’s a trend that’s good news and bad news. Maryland will now be joining other municipalities by taxing property owners based on the amount of impervious surfaces on their properties that leads to stormwater runoff. See the article: Chesapeake Bay Foundation on Maryland Rain Tax: Time to own up

They’re calling it a “rain tax,” and the more square footage of impervious surface you have, the more rain tax you’ll pay. Of course that’s bad news for property owners. But we think its good news for the environment. Properties with big roof tops and huge parking lots contribute disproportionately to the polluted stormwater run-off that overwhelms municipal systems or contaminates local waterways. So it makes sense to us that those property owners should pay their “fair share” for the treatment of that stormwater. In Chicago and other cities that have combined sewer and stormwater systems, big rain events spell big trouble when the volumes of rainfall create more flow than can be treated. The result in Chicago is that big storms result in a mixture of raw sewerage and stormwater being dumped untreated into the Chicago river – and even into our Lake Michigan potable water supply. (Yuck!) Chicago has spent BILLIONS on a huge detainage system (the Big Dig) that still isn’t big enough to hold the excess during large storm events.

We think the rain tax is also good news because it creates an incentive that rewards owners that reduce the impact of their impermeable surfaces by collecting and reusing that water for irrigation and other applications (Harvesting!). One reason more property owners do not harvest is because the value of the water savings alone presents a poor ROI vs. other conservation options. A “rain tax” adds another ROI contribution to the economics for a system. In addition to stormwater harvesting for reuse, green roofs, permeable pavers, vegetated swales and other tools are available to property owners to reduce their¬† property run-off and earn a credit against a “rain tax”.

We suggested a similar tax to Mayor Rahm Emanuel last year as a revenue tool for Chicago that would help our city raise funds for stormwater infrastructure as well as create that incentive the will promote stormwater reuse and other sustainable practices in the metropolitan area.

We’d like to hear your thoughts on the subject.¬† Should municipalities tax property owners on the stormwater run-off from their impermeable surfaces?