Soap Scum. Why it forms and how to remove it.

Soap Scum. Why it forms and how to remove it.

Soap scum is a pain in the ass. It can make your shower, glass, bath, basin, taps, tiles & even shower curtains, look gross.

We're all familiar with soap scum but many of us don't know what causes it or how to get rid of it.

In this blog post, we'll go over some of the common misconceptions about soap & how to tackle the dreaded scaley layer of soap scum.

Bar soap often gets the blame but really, it's mainly to do with the water in your area. Some people swear that gels and body washes don't cause any or as much soap scum and that's sorta true. We'll dive into why that is, below.

What is soap scum?

Soap scum is thick, initially sticky, rough, patchy and opaque white plaque that can build up in the corners of your shower, bath, and basins. 

What contributes to soap scum?

The biggest contributor to soap scum forming isn't soap. It's hard water and the dirt and oil coming off your skin, scalp and hair.

When hard water (water with a high calcium and magnesium content) is combined with most kinds of soap products (including shampoo) and the dirt/oil/skin cells being washed from your body, it will begin to form what we call, soap scum.

Be it handmade soap, liquid soap, body wash, shampoo, etc. If it bubbles & cleans any part of your hair or body, it will eventually turn into soap scum.

Regular tap water naturally contains harmless minerals, such as calcium & magnesium. They interact with the dirt & oil on our bodies or hair that the soap is trying to wash away & binds it all together. 

Most of that gets washed down the drain but if suds or splashes containing our dirt/oil/hard water combo (eww) are left on surfaces & not washed off, over time the deposits will thicken & create what we know (and hate) as soap scum.

How do I know if my water is hard or soft?

The water quality in Australia is highly regulated, however the hardness, is not. Depending on where you are in Australia, your water can vary quite a lot. Even in the same state or a few suburbs away!

Hard water

If you get limescale building up on your shower nozzle or in your kettle, you have hard water.

Soft water

If you need to use less than the usual amount of laundry detergent to get your clothes clean, or less soap to get a lather in your hards, then you have soft water.

Most of the country has soft water, rather than hard. Read below to see what kind of water you most likely have.

Note - there can also be big variances between metro and regional areas so please take this as a general guide.

  • QUEENSLAND                      HARD
  • ACT                                       SOFT
  • VICTORIA                              SOFT
  • TASMANIA                            SOFT
  • SOUTH AUSTRALIA             HARD

Why do I notice soap scum less when I use a shower gel?

Shower gels and body washes are often considered soap but have you noticed how it's not referred to as "soap" on the bottle? That's because it's not!

They are actually a gentle, synthetic detergent or "surfactant". They're not soap at all and are more closely related to washing up liquid than real, traditional soap.

But, they both perform the same kind of action. They bind with the dirt and oil molecules on our skin to be washed away down the drain.

The way that body washes and shampoos often reduce the amount of soap scum build-up is by adding and ingredient called Tetrasodium EDTA. 

Tetrasodium EDTA is a chelator (amongst other cosmetic properties), which means that it neutralises the metal ions in hard water, making the water softer so that soap scum takes longer to build up on surfaces.

It won't entirely prevent soap scum. Nothing can. That's why we still have to clean showers and sinks. Sucks, I know.

How to reduce soap scum?

All is not lost and there are ways to reduce the build-up of soap scum.

There's no magic wand sadly, it all comes down to regular cleaning. Which, to be honest, I'm still not totally across. My shower has soap scum right now! And it probably will for another few weeks.

But, there are a few tricks you can do each day to reduce the rate in which it builds up.

In the shower:

Thoroughly rinse off any remaining suds (especially shampoo suds!) from the tiles and shower pan. Use a squeegee to remove water from the glass and for extra protection, wipe with a towel or microfibre cloth.

If you're got a shower curtain, take it down and wash it in the washing machine once a month, then rehang to dry.

YUP, that sounds like a lot of work but the three minutes you invest each day could save you a lot of work in a few months. Plus, a dry shower won't get mould or mildew either (or that weird orange stuff) so there are benefits beyond simply slowing down soap scum.

In the bath:

After a bath, run a wet face washer around the "ring" and then wipe with a towel or microfibre cloth.

At the basin sink:

Once you've washed your hands for a minimum of twenty seconds, rub your clean hands around the sink to rinse any remaining suds or build-up off. Bonus points for wiping it out with a towel or microfibre cloth. 

Your bathroom sink can get soap scum fast but not so much from actual soap. It's often from toothpaste reside, hairspray, makeup and skincare products that make it into the sink, creating a film and then soap attaches to that. So don't be too hasty in blaming soap.

Updated 2022 - After writing this blog, I became really interested in testing out different cleaning methods and observing what happens when I don't clean. My biggest learning is that dirty feet mixed with shampooing your hair and not rinsing the shower floor properly was the BIGGEST factor in stubborn soap scum build up. If you've got timber floors or quickly duck outside the house to do something in the yard and your feet get a bit dirty, watch your shower floor. It'll get dirty really fast!

How to clean soap scum?

So long as you don't have fancy stone or marble surfaces, a cheap and easy way to remove soap scum is by making a paste of bicarb and vinegar. Wipe it onto the area with a non-scratchy cloth, leave for 15 mins and then buff off. Rinse clean and then dry. You can do the same on your tap ware too.

Don't want to use bicarb and vinegar? There's loads of natural and conventional cleaning products out there, so don't despair. Soap scum doesn't have to be so frustrating. Let the product do the work by sitting on the surface for the recommended amount of time before you scrub. It'll save your arms more work than is necessary. 

Just remember the one thing you should never do. Never use an abrasive scrubber on glass. It'll etch the glass and make limescale and soap scum build up faster. If you're in a rental or a home that's had previous owners and you don't know the history of the home, it's quite possible the glass is already damaged so might be in for a challenge.

To avoid soap scum, which Soap Cult product should I choose?

Glycerin soaps contain Tetrasodium EDTA which helps prevent soap scum build up.  Try Skull & Roses, Cauldron or Witchy Wisdom.

Soap Cult's traditional cold process body and facial soaps are a more natural soap and contain lashings of extra hydration to cushion the skin feel so they will get soap scum a bit faster. Don't let this put you off though! Simply rinse the bubbles off the tiles and half of your problems are avoided.

Shop our Body Soaps and Facial Soaps.


Soap scum can't really be avoided but it can be minimised by regular cleaning and keeping your wet surfaces, well, dry.

If you live in a hard water area like myself, I feel for you. You're not alone in the frustration of dealing with cleaning and soap scum.

After researching soap scum so thoroughly in order to write this blog post, I'm genuinely going to try the regular cleaning and drying surfaces trick to see if that helps my hard water woes.

If you try it, let me know below.

dark steamy shower


how to avoid soap scum and clean less often