Fight! For Your Right!…to know if there is sewage in your water!

It’s time for old regulations to get with the times!  Today on the blog we’ll review combined sewage overflow notification policies and how they are changing as technological improvements open the door for more accurate, proactive public notifications.

First of all, why would there ever be sewage in my water?

There are over 850 communities across the country that rely on combined sewage systems, meaning that when it rains, stormwater runoff from streets and parking lots flows into the same pipe system that carries municipal sewage. Normally, this flow is routed to wastewater treatment plants, but during rain events, these systems are often beyond capacity and spill over into local waterways. This is called a combined sewage overflow (CSO).

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Aren’t there already laws to deal with this?

Most communities dealing with CSOs have been under some form of Federal consent decree since the 1990s. These consent decrees require cities to develop a Long-Term Control Plan to manage and eliminate their sewage discharges. A significant part of each of these plans requires cities to properly warn the public when a CSO event occurs. The form these warnings come in varies by region and has often been general in nature.  For example, if you live in one if these regions, you may have seen signs to this effect. Or maybe you’ve just started to assume there is sewage in the water every time it rains. Or maybe you had no idea at all.

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Why is a general CSO warning not good enough?

The problem is that general warnings like signage at outfall sites are not specific enough to keep people safe. Depending on system conditions, CSOs can continue to flow for hours to days after the rain has stopped, and it is hard to confirm specific timing without being physically there to confirm.

As technology has advanced, many warning systems have moved past simple signage. Right now, the best tool many communities have to warn the public about threats from CSOs are stormwater models. Models are powerful tools, especially for planning purposes, but they are proving inadequate to warn the public about potentially serious pollution threats in real time, as the law intends. For example, a particular treatment plant may be dealing with capacity issues not reflected in the model, the physical environment may have changed due to development and may not be updated in the model, or precipitation patterns and timing may have changed in a way not yet incorporated into the model. All of these instances could lead to either under- or over-warning the public, potentially putting the community at risk. To date, 14 states have some form of CSO notification law on the books. These laws have been historically hard to comply with and enforce due to gaps in technology. In earlier decades, we did what we could. Now, we can do better!

Smarter cities, smarter regulations

Cities everywhere are working to get smarter, more connected, and efficient. This has opened up an opportunity to provide a higher level of safety to the general public during CSO events, and environmental groups are stepping up to seize it.

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In 2012 the Sewage Pollution Right to Know Act was signed into law in New York State. This law requires treatment plants to immediately (or at least within 2 hours) report discharges of untreated or partially treated sewage that is not in compliance with any prior permit. This past October, Pace Environmental Litigation Clinic challenged New York City’s Department of Environmental Protection, claiming that they are in violation of this law because they report discharges only when a model predicts that a water quality violation has occurred, not in real time as each CSO is actually occurring. According to Riverkeeper “this notification procedure jeopardizes the health of those who live, work or recreate on the waters and may come into contact with raw sewage. Raw sewage contamination can cause gastroenteritis, skin rashes, pinkeye, ear, nose and throat problems, respiratory infections, meningitis, hepatitis and other illnesses… when boaters, anglers and, yes, swimmers get into the water in New York City, they should be alerted when the nearby outfalls are discharging raw sewage and industrial waste.”

Massachusetts is undertaking a similar effort. The Act Promoting Awareness of Sewage Pollution in Public Waters seeks to make public warnings in the state more transparent. The bill would require CSO operators to report a discharge, its location, and its volume to local health departments within 2 hours of 1st occurrence, along with any recommendations such as not fishing or swimming for the next 72 hours.

Phil Guerin, director of Worcester’s sewer system and president of the Massachusetts Coalition for Water Resources Stewardship, says that it’s not sending the notification that is the issue, it’s actually knowing whether a CSO event is actually happening that is the hard part. He notes that, historically, the only way to know if most CSOs were occurring was to send someone out to visually inspect them, which, of course, is not a sustainable (or even safe!) process. This has made effectively enforcing and/or meaningfully complying with CSO notification policies has been hard to do. Luckily, technology is starting to close that gap.

Guerin notes that where outfalls have had sensors installed, CSO detection is a different story. We have  reached a point where almost anything in a city can be made “smarter,” and sewers are right up there on the priority list. Though it would not have been feasible in the past to fit each outfall in a region with its own set of sensors, technology has scaled to the point where it is not only possible, but is beginning to be mandatory. Sewers and outfalls equipped with sensors allow operators to know, often in real time, when a CSO is occurring without having to travel across a city during a potentially dangerous storm event. Having these tools on hand opens up the possibility of enforcing CSO warning policies as intended—and providing the public with a heightened level of safety.

What does real-time CSO detection look like?

CSO detection in real-time can take many forms, from simple level sensors to more advanced systems with real-time controls. At StormSensor, we have designed a system of networked sensors and cloud-based software to detect and track CSOs throughout your system. Our network allows you to set notifications for CSO start and stop times, auto-generates an event summary, and allows you to track events spatially and graphically. Here’s what it looks like:



Interested in real-time CSO detection?

Contact us to learn more!

About the author

Suzie Housely

Talk stormwater with Suzie has over a decade of experience in the Stormwater industry including both government and academic work. She leans on her experience to meaningfully interpret scientific studies and government policies to communicate a practical message. Suzie lives just outside Nashville, TN and gets outside whenever she can to explore nature with her husband and two small children.