Clean soap scum from drains, bathroomWhat Is Soap Scum?

Soap scum is the solid white residue that clings to bathtubs, shower stalls, drains and pipes. It forms when soap and mineral-containing water mix together. Groundwater in the Pacific Northwest contains minerals, but hard water is characterized by relatively large amounts of calcium and magnesium. Oregon water tends to be soft, but there are plenty of nearby regions, such as east Oregon and Washington state that rely primarily on hard water.

Regardless of what area of the PNW you’re living in, soap scum can find a home just about anywhere in your shower or bath. 

How Does Soap Scum Cause Plumbing Problems?

When the minerals in hard water react with the fatty acids in soap, they create lime soap, otherwise known as soap scum. Scum builds up over time, attracting mildew and mold. The scum is a nuisance because it can clog your drain. It’s also gross and potentially unhealthy because it plays host to bacteria. Soap scum can be a problem in the kitchen sink, but it tends to be more common in the shower or bath.

Portland water: Is it hard or soft?

Portland’s water is naturally soft. The city gets water from the Bull Run Watershed. The Portland Water Bureau serves the tri-county area. If you live in Multnomah, Washington or Clackamas counties, your municipal water comes mainly from Portland and the Bull Run.

Even though the city’s water is soft, you may still have a problem with soap scum. Many places in Oregon use a mix of sources that combine both hard and soft water. For example, ff you’re not connected to public water but instead use a well, you could have hard water. Whatever the source, if you see water spots on your drinking glasses, you have minerals in your water.  

How to Prevent Soap Scum From Clogging the Drain

You can clean soap scum from your drains in several ways. Use one of the following methods about once a week. If you clean regularly, you’ll remove scum before it grows into a clog.

  • Hot water: Boil water and pour it down the drain. This simple action will melt soap scum clinging to the pipes. Follow by running hot water for a few minutes. Read about other ways to clean drains without the use of harsh chemicals.
  • Clean with baking soda: Mix baking soda and water in a measuring cup and pour it down the drain. Use the ratio of 1 teaspoon of baking soda per 1 gallon of water on the first attempt. If that doesn’t work bump it up to 1 teaspoon per 1 quart of water (do not exceed 2 teaspoons in one day ). The mixture will quickly eat through soap scum. Baking soda deodorizes the drain in addition to keeping it cleaner.
  • Ammonia: If hot water didn’t do the trick, pour ammonia down the drain. Then, pour more boiling water. Flush by running hot water. This method may work if your drain is slow because of scum. Be sure to run the fan and open a window. Ammonia odors can be overwhelming.

    Caution: Never mix chlorine bleach or vinegar with ammonia. They will form a toxic mix of vapors that can send you to the emergency room.

 Other Ways to Keep Your Drains Clean

In addition to flushing away soap scum, prevent clogs by taking care of your drains.  Here are two simple, cheap and effective ways to keep your pipes cleaner:

  • Use a mesh trap: If you’re not using a mesh trap, purchase one for each bath or shower drain. Mesh is the best type of trap for catching soap scum, hair and other things that contribute to clogs.
  • Don’t use the drain as a garbage disposal: Anything that goes down the pipe can potentially stick to soap scum and worsen a clog. Hair, food, grease and grooming products contribute to the buildup. A mesh trap will screen out many things, but be careful of what you pour in the drain. Properly dispose of kitchen grease and scraps by placing them in the garbage or compost bin. Never pour things such as leftover paint or solvents down the drain. Aside from being bad for the plumbing, they contaminate the environment.

Need a Portland-area plumber?

Contact Meticulous Plumbing for help with soap scum, clogged drains or any other plumbing problems. We’re a family-owned plumbing company in Portland, Oregon.

Updated Jan. 5, 2017. Originally published Feb. 25, 2015.

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