Still, an estimated 300 million gallons of feces-infested water had already entered the Potomac as of Tuesday, according to a report<\/a> by the nonprofit Potomac Riverkeeper Network. The group has also been performing independent testing of river water, which so far has revealed dangerously high E. coli levels at sites throughout the region\u2014including contamination roughly 12,000 times the safe limit for human contact just downstream of the break near Cabin John. Four miles downstream of the leak, at Fletchers Cove in DC, riverkeepers measured E.coli levels that were still 60 times higher than what\u2019s considered safe.<\/p>\n \u201cWe are aware of testing done by the Potomac Riverkeeper that found high levels of bacteria in the waterway near the spill, as would be expected,\u201d the Maryland Department of the Environment told\u00a0Washingtonian in a statement Friday. \u201cDC Water has indicated that it will do water testing in connection with its cleanup of the spill. We also plan to do water monitoring and will stay engaged in the long term to ensure that the spill and its environmental impacts are remediated.\u201d<\/p>\n One major silver lining of this literal shitshow: Our local drinking water supply should not be affected. \u201cThe overflow is downstream of the Washington Aqueduct\u2019s intakes for drinking water at Great Falls,\u201d DC Water spokesperson Sherri Lewis told\u00a0Washingtonian\u00a0in a statement Tuesday. \u201cAdditionally, the Potomac Interceptor is a sanitary sewer line; and the wastewater system and the drinking water system are completely separate.\u201d But a raw sewage spill of this magnitude still presents risks to public health and wildlife. Here\u2019s what to keep in mind, even now that the leak is largely contained.<\/p>\n Though gratitude is hard to source from such muddied waters, experts are thankful that this ordeal is happening now and not during the spring or summer. \u201cWe\u2019re lucky the sewage spill happened when both the recreational activities are low, as well as the biological and animal activities,\u201d says Hedrick Belin, president of the Potomac Conservancy<\/a>. \u201cIt\u2019d be a different conversation, I think, if this were heading into July 4 weekend.\u201d But even if you\u2019re not planning to take your canoe for a spin in the city\u2019s Arctic temperatures any time soon, there are a few public health concerns to keep in mind. Lest we forget: \u201cEverything that you find in raw sewage\u2014bacteria, but also pathogens, parasites\u2014are in the Potomac River now,\u201d says Dean Naujoks of the Potomac Riverkeeper Network<\/a>.<\/p>\n Maryland\u2019s Department of the Environment has closed an upper segment of the river<\/a> in Charles County due to concerns about shellfish harvesting. \u201cWe used computer simulations to figure out a \u2018worst-case\u2019 scenario on how the pollution could travel and be diluted to determine the closure area,\u201d which \u201cincludes the Potomac River from Charles County and bordering Virginia areas, extending from the Port Tobacco River region down to the U.S. Route 301 bridge,\u201d the department told Washingtonian in its statement. The agency says it has \u201cno evidence shellfish outside of the defined emergency closure area have been affected\u201d at this time, but they plan to collect water samples in shellfish harvesting areas next week.<\/p>\n \u201cThe actual worst exposure scenario down the river and toward the bay is shellfish,\u201d says Lynn Goldman, a professor of environmental and occupational health at George Washington University\u2019s Milken Institute School of Public Health. Because shellfish are filter-feeders, they take in a lot of water. \u201cThose advisories, typically after a sewage spill like this, have to go on for three weeks, because that\u2019s how long it takes to clear these viruses\u2014mostly\u2014out of the shellfish.\u201d\u00a0The Potomac Riverkeeper Network would like to see<\/a> the DC government issue a similar shellfish advisory. \u201cWe have not made any plans as yet for that, but we do support our regional partners in their messaging, so it is possible we will do so,\u201d the DC Department of Environment and Environment told\u00a0Washingtonian\u00a0in a statement Friday. (Shellfish growing areas on the Virginia side of the Potomac, riverkeepers say, are not currently affected by the spill.)<\/p>\n \u201cThe great thing, in terms of most ways you can be exposed to the the waste that was emitted, is that there is dilution\u2014and that is really helpful when it comes to people who just have contact with the water, are floating on the water, swimming in the water, their dogs are in the water,\u201d Goldman says. \u201cIf you\u2019re not super close to a spill, there\u2019s not a very high concentration of the pathogens that certainly are in the fecal waste.\u201d<\/p>\n And surely nobody is planning to go swimming in the river anytime soon, which you can\u2019t really do anyway<\/a>. Actually, wait: In a nearly poetic display of irony, the Chesapeake Climate Action Network\u2019s annual Polar Bear Plunge<\/a> at National Harbor is scheduled for February 21. It was originally booked for February 7; organizers decided to delay it \u201cout of an abundance of caution,\u201d a CCAN spokesperson tells\u00a0Washingtonian. Should you partake? Stay abreast of local testing developments. \u201cIf I were thinking about an event where a lot of people are in the water, I\u2019d be testing the water on any day, much less after a spill like this,\u201d Goldman says. \u201cBecause any day there can be overflows\u2014even if they\u2019re not big ones, there could be smaller ones that are even closer to that location and that could have more risk to the people in that stretch of\u00a0 the river because they\u2019re closer to it.\u201d\u00a0<\/p>\n As of now, it should be safe to stand on land within the vicinity of most of the Potomac. \u201cIf I were walking my dog by the river right now, unless I were right there by where the break occurred, where there might still be leakage, I would not be so concerned,\u201d Goldman says. \u201cAnd I\u2019d be quick to say that any day when we have a heavy rain, there are areas that have overflows around not only the Potomac, but also Rock Creek and other other waterways.\u201d<\/p>\n What\u2019s the risk to local wildlife?<\/p>\n Most of the fish swimming in the most contaminated waters have probably died, Belin says. \u201cBut as the sewage plume moves downstream and gets more diluted\u2014it\u2019s not covering the whole width of the river in some places yet\u2014it\u2019s certainly unclear what this might mean.\u201d The Potomac Conservancy releases a report card every couple of years evaluating the environmental health of the river; since 2020, the river\u2019s shad population has maintained an \u201cA\u201d grade. That\u2019s a big deal, since the migratory fish have been steadily making a comeback<\/a> since the Interstate Commission on the Potomac River Basin made moves in the 1990s to refresh a dwindling population caused by water pollution and dam-building in the 1970s. \u201cThere\u2019s been a lot of hard work to get it to that point,\u201d Belin says. \u201cHopefully, this sewage spill clears up and is gone by the time they start running in the spring, because otherwise that\u2019ll have both recreational and economic impacts.\u201d<\/p>\n At the end of the day, \u201cit\u2019s pretty unprecedented, where there\u2019s been a massive spill of this size and then [part of it] gets kind of trapped and locked in ice,\u201d Naujoks says. Experts are not sure exactly what will happen when that ice melts.<\/p>\n When will the water stop being poopy?<\/p>\n The natural flow of the river will eventually carry the sewage out of the waterway itself, according to Belin. \u201cIf you think about shutting off the faucet, if you will, of sewage into the river\u2014at that point, it becomes, \u2018Well, how long is it going to take for it to move down the river, and how is it going to mix?\u2019 \u201d He estimates that approximately two months from now, in March or April, \u201chopefully this sewage plume [will have] completely dispersed.\u201d<\/p>\n Unfortunately, and I hate to report this, there have been some spots along the C&O Canal where sewage has overflowed onto the land. \u201cWhen [the water] sort of settles, there\u2019s a good chance\u2014on the shorelines downstream and then in the basin of the canal\u2014there could be manure,\u201d he adds. \u201cKeep in mind, that definitely has to be cleaned up, but it\u2019s really cold out.\u201d That means the bacteria living in this shipwrecked poop will likely die much more quickly than it would have during warmer weather, since it thrives in human and animal body-adjacent temperatures.\u00a0<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/01\/PC-Potomac-Riverkeeper-Network.jpg\" "\\"PC")
Dean Naujoks of the Potomac Riverkeeper Network tests contaminated water for pathogens. Photograph courtesy of the Potomac Riverkeeper Network.
\nWhat precautions should you take around the river?<\/p>\n
![\"Kate](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/01\/ad4e91ba02bb1322408a56cc918389ef192fcff67883a828e926f4db99692032.png\")
<\/p>\n","protected":false},"excerpt":{"rendered":"Photograph by Burton Gray. Unless you\u2019ve been living under a rock (or a cascade of \u201csnowcrete,\u201d which might…\n","protected":false},"author":2,"featured_media":440933,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[192,79],"class_list":["post-440932","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-environment","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/440932","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=440932"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/440932\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/440933"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=440932"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=440932"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=440932"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}