In Berlin, toilets flush directly into the river (but it’s not just Berlin)

Raw sewage flows into the waterways in Berlin and many other cities on a regular basis. Some are doing more about it than others.

When you flush your toilet in Berlin during a moderate-to-heavy rainstorm, it goes directly into the Spree river that runs through the city, or into one of its several canals. This happens on 30 to 40 days each year, sometimes as many as 60. This post is a documentation of just a few of the 120-odd outlets where the untreated sewage enters the waterways. Many cities around the world have the same problem, but many of them have projects for combatting it costing into the billions, which Berlin does not. I think we can safely say that if you’re piping raw sewage into your river and doing less to change the situation than more or less all your peers, you forfeit your claims to being an eco-mecca, which I point out only because that is precisely Berlin’s image.

Further, to inform the public about the sewer outlets and whether they’re overflowing, some water authorities have online interactive maps with real-time updates. Many have signs posted at each outlet in multiple languages, often with an ID number and phone number to call in case of malfunction. Scores of agencies and organizations in the U.S. have hundreds of K-12 lesson plans and learning activites on the topic available for free download. None of this exists in Berlin or, apparently, anywhere else in Germany.

Regularly-occurring mass fish die-offs are just one reason the E.U. is taking legal action against Germany over its water quality

The releases of untreated sewage are known as combined sewer overflows (CSOs), and the reason they’re important is that the pollution from them persists over the whole year. The yearly overflows on Berlin’s largest canal alone contain enough sewage to fill its entire length twice over. The pollution is severe enough that not one of Berlin’s rivers or lakes meets the European Union’s legal standards for water quality and ecological condition, which they were all required to meet by 2015. Twenty-one years after the law’s enactment in 2000, the city still doesn’t have a compliance plan or an estimate of when, if ever, it will meet the requirements. As a result, the E.U. has taken the first steps towards lawsuits (which under E.U. law are filed against countries, not individual cities) that can result in fines of hundreds of thousands of euros per day.

Visualizing sewage benefits everyone

Cleveland is one of numerous cities (Philadelphia, Seattle, New York for starters) that shows you where the CSOs are and if they’re overflowing right now…

…clicking on each CSO brings up detailed data…

… and a photo of the outlet.


Seattle posts signs at its CSO outfalls in five languages…

What Berlin does have is a map in pdf format which was created by a city agency but never officailly published. I only stumbled upon it at one anonymous person’s website; it’s there in the open if you know how to search for it, but it’s unclear whether they had any authorization to publish it. At any rate it’s a slapdash affair, with numbering of the outlets that has nothing to do with the numbers painted on the outlets themselves, as in the photos I took on-site, below.

Berlin is not the only city with a CSO problem. Most cities that were of any substantial size in the early 1900s have it too, because that’s when their sewer lines were built, using a now-antiquated system. What makes Berlin stand out is how little the city is doing to solve it compared to other places. Not just compared to progressive places like Amsterdam or Copenhagen, but even compared to many just-average American cities.

So far, my attempts to find out how this is possible in the capital of the world’s fourth largest economy, a presumed leader in technology, and a self-proclaimed world capital of environmental consciousness where the Green Party has been in the city council for 40 years have not been successful. There is no substantial public conversation on CSOs in Berlin. (The nearest thing is a plan to block off an arm of the Spree and build a swimming pool in it, which in a remarkable stroke of magical thinking is being billed as a water quality improvement project – a wildly popular environmental Theranos except the bubble hasn’t burst yet.)

By contrast, in New York, which is just three times the size of Berlin, 70 organizations have formed a coalition dedicated entirely to CSOs, called Stormwater Infrastructure Matters, or SWIM (the name pre-dates Black Lives Matter by a decade or so). There are towns and counties a fraction of Berlin’s size such as New Haven and Milwaukee with whole organizations for citizen outreach and action on stormwater.

The bill for unbridled growth has arrived and it’s not cheap

Many cities have expensive programs to deal with the situation and fixed targets to reduce the overflows. New York is spending $6 billion, Honolulu $5bn, St. Louis $4.7bn, Cincinnati $3.3bn, Cleveland $3bn, Washington $2.6bn, Kansas City $2.4bn, Portland $1.4bn, Atlanta $1.1bn. Most of these cities are considerably smaller than Berlin.

Berlin city is undertaking some measures and spending money on the problem but there is no specific plan with targets and budgets for reducing the CSOs. On the surface it may appear there is some of the green infrastructure that has been the industry standard elsewhere for twenty years now and is much cheaper and better for the climate than the older types of “grey” infrastructure.

But when you look closer, you discover green infrastructure for CSOs is only used on private property as a purely voluntary measure. There’s no follow-up to find out how much these efforts actually reduce the sewage overflows, which is the whole point of having them in the first place. Berlin has no green infrastructure on public property and no plans to have any.

Politicians are not well informed on the issue. At a recent hearing, the speaker for environment for a progressive party asked if we could just tear out the whole sewer system and replace it. When someone like that asks a question like that, in 2021, you have a serious problem. The city council should have cleared up this point thirty years ago, because no large city has ever has replaced their entire CSO system and never will. For Berlin it would cost many billions – I’d guess 20 to 50 billion – and would take something like 50 years. For comparison, it took Portland, a much smaller city, thirty years and several billion dollars to reduce their CSOs using a variety of methods such as retrofitted structures – but not a complete replacement of the system.

The antiquated sewer system is called a combined system because it collects both stormwater from the streets and wastewater from kitchens, bathrooms and industry into one combined pipe system that leads to the treatment plants. The catch is that the system has overflow pipes that serve as safety valves when rainfall overloads the system. The overflow pipes carry the combined rainwater and raw sewage directly into the rivers and lakes. The consequences for water quality and the health of rivers, lakes and oceans are devastating.

Farmers could see where this was going

Combined sewers were acceptable 100 years ago, before there was much concern over water pollution. Further, the overflows are more common now than they were originally. One reason is that the rate of sealing over the land’s surface with pavement has grown continually for a century and shows few signs of slowing down. As a result, whenever it rains, more rainwater enters the system than it used to, instead of soaking into the soil.

Farmers could see this coming, if this highly sophisticated depiction of the situation from 1956 is anything to go by.  The hydrological and ecological principles haven’t changed, and yet the pages are from a book not by an ecologiist or hydrologist but by a farmer and artist.

The other reason for the increased CSOs is that the climate crisis is increasing the intensity of rainstorms. This is why doing something about CSOs is an essential part of climate adaptation and resilience.

Separate sewer systems for wastewater and stormwater first appeared about 100 years ago, almost entirely in newly built districts and in exisiting parts of cities that had never had a sewer system to speak of. I’ve never heard of a case where a city replaced an existing combined sewer system with a separated one although this could have happened somewhere.

Separete sewer systems don’t have the problems with raw sewage because one set of pipes carries the wastewater to the treatment plants and another carries the stormwater, untreated, to the waterways. They are not off the hook for water pollution though, because stormwater carries pollution from streets, rooftops, lawns and agriculture. It’s not as polluted as sewage itself but it’s still polluted. So nationally there is a crisis with  stormwater runoff on top of the acute crisis with CSOs.

Communities in the lower 49 with combined systems (EPA)

In the U.S., twelve percent of the population lives in the roughly 700 localities that have combined sewers. The E.P.A. has sued over 200 of them for water quality violations since the mid-1990s, resulting in the aforementioned expensive imporvements to the systems. The German government does not sue cities in this way.

What a sewage outfall actually looks like

What follows is a sample of Berlin’s CSO outlets. They may look unassuming but they are responsible for annual blooms of toxin-producing algae that each year kill a few dogs and make children seriously ill when they fail to follow the city’s spontaneous, short-term swimming bans. The CSOs also cause fish die-offs where thousands of dead fish float to the surface.

Digression. Next to #45 is one of the best things in Berlin. It’s a vending machine for little toys which looks as though it could have been there since the 1970s and would weigh 500 pounds. It’s hidden on a canal bank just off a heavily-trafficked street in a desolate and miserably ugly business district with no life, no shops, and no people (although it’s directly in the middle of the city). Incredibly, it works. In a notoriously broken-down city (ask any Berliner, or any German) it almost feels like the vending machine is the only thing in Berlin in good working order that does what it’s supposed to do. I bought a super ball (20 cents) and a tiny doll (50 cents) with a suction cup on the back.




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