Does Sewage Go Into The Ocean (The Answer May Surprise You)

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Does sewage go into the ocean after we flush? What happens to it?

Sewage is a tough subject to think about. Most of us use the bathroom without thinking about where the waste goes after we flush. Claiming ignorance is understandable sometimes a good thing.

However, it’s important to know where sewage goes so you can stay safe on the beach and in the ocean!

In this article I’ll share if sewage goes in the ocean and I’ll briefly breakdown how the treatment process works.

Depending on where you live, sewage in the ocean may or may not be a problem. I’ll also share situations when you might not want to swim in the ocean.

How Does Sewage End Up In The Ocean

#1 Depends On The Country

Sewage is processed differently depending on the country and on the location.

In more developed countries like the United States, municipalities have sewage treatment plants that separate the liquid from the sludge. But people who live in rural areas rely on septic tanks which hold and process sewage then slowly release it into the ground (a household treatment process).

In less developed countries municipalities sometimes have treatment facilities.  If the infrastructure is not in place sewage can enter lakes, rivers, and oceans directly.

If you’re in the U.S chances are that you don’t have to worry about sewage in the ocean. If you’re at a remote beach in a tropical land there’s a good chance a sewage line empties into the ocean (or septic drains close to the beach).

#2 Depends On The Sewage Treatment Process

During the sewage treatment process the liquid is separated from the sludge.

The liquid goes through a process of chlorination and filtration and in more advanced systems the water can be reused for parks, landscaping, and golf courses (not for drinking). Ideally there is no discharge at all – all water is recycled! In less advanced systems the water is dispersed into a nearby body of water such as rivers and oceans.

The sludge is the nasty stuff that’s a result of our waste. The polite term is biowaste. Once it’s separated it goes through a sterilization process and it can also be used to collect methane gas for electricity.

>> read my article about peeing in the ocean

Once the sludge is thoroughly digested it can be dried and used as a fertilizer, fuel, and as a general soil amendment.

#3 Historical Practices

Before treatment facilities became more advanced, almost all coastal cities in the U.S. disposed of their sewage in the bays and oceans. The onslaught of nutrients destroyed marine ecosystems and bacteria thrived in the water which made swimming a risky endeavor.

Many people in the U.S. still worry about sewage in the ocean but it’s no longer something to worry about when you’re spending a day at the beach.

So, Does Sewage Go Into The Ocean

The answer is yes, but not in the way you might think. In the U.S. sewage first goes to treatment facilities where it’s processed into liquid and solids.

After the liquid is cleaned (filtration and chlorine) it can be reintroduced into our rivers and oceans.

Modern treatment plants don’t allow actual fecal matter to enter our oceans, however, it’s not the case for all countries. Older infrastructure, overflows, and broken sewage lines can cause millions of gallons of untreated sewage to seep into rivers and oceans.

This not only damages marine life but also subjects beachgoers to harmful bacteria.

One example of sewage in the ocean is in San Diego, California. San Diego shares a border with Tijuana, Mexico and sewage treatment facilities work much differently in their respective cities.

Even though San Diego does a great job of treating and recycling sewage, beachgoers must be aware of the sewage situation in Tijuana.

Tijuana has sewage treatment facilities however they are often overwhelmed and overcapacity. The sewage system often leaks and causes raw sewage to flow directly into the Tijuana River (more information).

This river exits into the Pacific Ocean and during certain times of year (and certain tides) can pose a health risk to people swimming and surfing in San Diego.

Just because sewage isn’t entering the water in your city, doesn’t mean you can’t be affected by nearby cities.


You might be on the beach, thinking about whether to go in the ocean or not and thought, “does sewage go into the ocean”. It’s a common thought and something you should consider.

After all, who wants to go in the water if there is human waste.

In some parts of the world sewage is still dumped into the ocean, however cities are working hard to reduce their negative impact on the environment and make the ocean a more enjoyable place to be.

A clean ocean means healthier wildlife, more industry (like fishing), and more tourism.

If you’re in the United States, chances are you don’t have to worry about sewage going into the ocean. Treated water from your sewage will enter the water but only after the bacteria has been removed.

The more hazardous waste (sludge) will be process and utilized (or burned) on land.

You can feel confident visiting the beach and entering the ocean for a swim without having to worry about sewage!