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Can You Pour Milk Down the Drain? The Surprising Answer!

Pouring millk down the drain

It may not seem like a big deal, and you probably dump a lot of stuff down your drain without giving it a second thought. However, using your sink as a makeshift trash can is not smart, even if you have a garbage disposal. That includes things like potato skins and coffee grounds. It also applies to milk and other dairy products.

It’s not a stretch to think that something we can consume is safe to pour down the drain. However, it’s more complicated than it sounds. Keep reading to learn more.

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The Environmental Cost

You likely won’t have any serious issues from pouring milk down the drain every once in a while, but it isn’t something that you should do regularly, or at all.  While it seems like pouring milk down the drain is harmless, it may surprise you to learn that milk disposal is regulated at the state and federal levels.1 It’s even a punishable offense in the United Kingdom.2 After all, it is an animal by-product, which explains the legalities of managing it properly. The problem with milk is its high phosphorus and nitrogen content.3 Excess amounts can foul waterways and adversely affect aquatic plant and animal life.

These nutrients can cause algal blooms, which can deplete the oxygen in the water. It’s not unlike what happens on a small scale in an aquarium that isn’t maintained properly. Affected drinking water can also harm young children and livestock that consume it. It’s worth noting that 70% of our freshwater comes from surface water sources, like lakes.4 Therefore, it behooves us to keep it clean.

Pouring milk into glass
Image By: NaturalBox, Shutterstock

Problems Building Up

Pouring milk down the drain can also cause issues closer to home. Remember that it contains fat, even in liquid form. It can coat the inside of your plumbing and build up over time, clinging to the other junk in your pipes, like grease and hair. You may notice your sink becoming slow draining, which means an isolated problem. The clog may loosen with heavy water use. Sometimes, it doesn’t.

The Cost of Pouring Milk Down the Drain

Clogged drains are one of the most common plumbing repair jobs. Commercial products will handle small blockages close to the drain. Unfortunately, small ones often become big ones, requiring a professional to fix the problem. You can expect to pay an average of $150–$200 to have a contractor snake out your pipes. That’s saying nothing about the odor and inconvenience, either.

Watching what you pour down the drain is particularly essential if your home is on a well. A properly constructed structure will keep harmful bacteria out of the system. The stuff you pour into the sink can cause other issues that are far more costly than a clogged drain.

Solutions for Expired Milk

According to, a container of milk, regardless of its fat content, will last about 7 days past the carton’s sell-by date as long as you keep it under 40℉. The best way to deal with milk is to drink or use it before it expires. Otherwise, you can freeze it for up to 4 months.

You may read about some people using spoiled milk in recipes. However, we suggest you don’t use it, as per the recommendation of Consumer Reports. You can dilute the excess milk with water and use it to fertilize your plants. However, a risk of bacterial development and spoilage also exists if you do it frequently. The best solution is only to buy and use what you can use before it expires.


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Final Thoughts

People often think of things as out of sight, out of mind when it comes to pouring things down the drain. However, it’s essential to remember that it’s not a liquid trash can. What you put down the drain ends up in your city’s wastewater plants with the potential to harm the environment. Buying and consuming only what you need is an excellent way to safeguard against unnecessary food waste.

Featured Image Credit: Ron Maxwell, Shutterstock


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