Rain, Runoff and Your Dog: Boston's Harbor Water Is Off-Limits Until Wednesday

Boston Made, Inc.Office of the Founder & CEO

From the desk of Nathan StricklandBoston, Massachusetts · October 13, 2026

Dear Sir or Madam,

BOSTON, Oct. 13, 2026 — Sunday night’s soaking rain did what heavy rain in Boston often does: it overwhelmed the old pipes under the city, and a mix of stormwater and sewage went into the harbor. On Monday, the Boston Public Health Commission issued a public health warning for two of the most popular waterfront walking spots in the city. If your dog’s favorite stroll runs along the Fort Point Channel or the Inner Harbor, today is a leash-short, no-swim, no-drinking day.

What happened

Parts of Boston’s sewer system are “combined,” meaning rainwater and household wastewater share the same pipes. When a big storm pushes more water through than the system can handle, it releases the overflow into nearby water rather than letting it back up into homes and streets. That is called a combined sewer overflow, or CSO.

The National Weather Service had forecast roughly three-quarters of an inch to an inch of rain for Sunday evening and overnight. According to the city’s notice, two overflows were reported:

Fort Point Channel (Boston Water and Sewer Commission outfall): from about 10:50 p.m. Sunday to 1:05 a.m. Monday, affecting the channel, Downtown and the South Boston waterfront.
Inner Harbor (MWRA’s Prison Point facility, a treated discharge): from about 9:26 p.m. Sunday to 1:56 a.m. Monday.

Both advisories run for 48 hours after each overflow ended, which means they expire in the early hours of Wednesday, Oct. 14. The city also notes that smaller overflows below its two-hour reporting threshold may have occurred elsewhere.

Why it matters for dogs

The city’s guidance is written for people, but dogs are the ones most likely to wade in, lap up a mouthful or roll in something they shouldn’t. The health commission warns of increased risk from bacteria and other pollutants in urban runoff and partly treated wastewater, and its standing advice is to avoid contact with affected water for at least 48 hours after a discharge, during rainstorms, and for 48 hours after rain ends.

There is also a broader fall risk. The CDC notes that heavy rain can wash animal urine into puddles, streams and floodwater, spreading leptospirosis, a bacterial infection that can affect dogs and people and can survive in water or soil for weeks. Standing puddles after a storm are not automatically dangerous, but they are not a water bowl either.

A simple plan for this week

Through Wednesday morning: keep dogs out of the Fort Point Channel and Inner Harbor water entirely. Use a shorter leash along the Harborwalk edges.
Bring your own water. A collapsible bowl and a bottle mean your dog has no reason to drink from puddles or the harbor.
Rinse and dry. If your dog does get wet near the waterfront, rinse paws, legs and belly with clean water at home and towel off.
Watch the sky, not just the calendar. Forecasters expected more showers and possible thunderstorms Tuesday night. Any new heavy rain can trigger new overflows and restart the 48-hour clock.
Know the signs. Vomiting, diarrhea, lethargy, refusing food or unusual thirst after water exposure are reasons to call your veterinarian, and to mention where your dog was.
Check before you go. Boston Water and Sewer posts harbor and Fort Point notices; the MWRA posts alerts for the Charles River and its own outfalls.

Fenway’s Take

The harbor is for looking, this week. Fenway loves a waterfront walk as much as any Boston pup, and the Seaport and Fort Point are some of the best people-watching (and pigeon-watching) in the city. A two-day pause is a small price for a healthy dog.

Boston’s pipes are older than all of us. Overflows are not a scandal; they are a design from another century working the way it was built to. The city and the MWRA have spent decades cutting them down, and the alerts exist precisely so families can make smart choices. The least we can do is read them.

Make the bowl part of the leash. The single best habit for fall: never leave the house without water for your dog. It ends the puddle problem before it starts, in every season.

Fenway’s water-safety quiz

Tap an answer to see how you did.

Talk it over

Where is your dog’s favorite waterfront walk in Boston, and what is your backup route on advisory days?
Would you sign up for text alerts about sewer overflows if the city offered them by neighborhood?
What is in your dog’s rainy-day walk kit?

Sources

Featured image: AI-generated illustration (DeepAI). This article is general information, not veterinary advice; call your veterinarian with concerns about your pet.