The best shampoo bars for hard water and how to use them

Not all types of shampoo bars work well in hard water. This is due to a combination of the ingredients they use and their PH level. If you live in a hard water area, the best shampoo bars to use are going to be those that contain cleansing ingredients like surfactants.

Here are some of my favourite shampoo bars that I’ve used that work perfectly in hard water:

Sage Folk is based in Norfolk, an area that has very hard water. I tried for over a year to transition to using “natural shampoo” (shampoo that doesn’t contain surfactants). My experience was that I had to use an increased amount of water to wash the natural shampoo out of my hair, and still felt like I had build-up after washing.

Because of this experience, I would not recommend natural shampoo bars in hard water areas. Don’t despair though, I stock a whole range of shampoo bars that work in hard water. I’ve tried and tested each one myself in the hard water of Norfolk and love the consistent results they all offer.

Lemon Verbena Scented Shampoo Bar by Authentic House

Wild Ona Shampoo Bars - Available in Pure, Green Queen and Balance | Sage Folk

Monoi de Tahiti Shampoo Bar for dry and frizzy hair types - Bain & Savon | Sage Folk

How to use shampoo bars in hard water

If you’ve chosen a shampoo bar with a surfactant ingredient, then it’s going to work very much like liquid shampoo in terms of washing results and you shouldn’t be left with the feeling of product build up or a waxy or chalky residue in your hair.

To use a shampoo bar:

  • thoroughly wet your hair
  • moisten the shampoo bar and lather it up between your hands
  • transfer the lather to your hair and work in
  • rinse out and condition

If you have particularly long or thick hair, or if you simply find it easier to do so, you can also rub the lathered up shampoo bar directly onto your hair, and the lengths of it, to distribute the suds throughout it that way.

Which solid shampoos to avoid using in hard water

Natural shampoo bars are usually the culprits when it comes to undesirable wash results in hard water areas. This is because they are most typically soap based and don’t contain any ingredients like surfactants to boost their cleansing properties.

If you’ve had first-hand experience of that waxy residue left in your hair after using a shampoo bar, then you’ve most likely been using a natural shampoo.

Having said that, some people will get on perfectly fine with natural shampoo bars and enjoy using them. For those that do, I stock a range of natural shampoo bars handmade by lovely, independent UK makers.

Why doesn’t natural shampoo work well in hard water?

Hard water has a high mineral content which can react with the ingredients in natural shampoo and leave a residue in your hair, no matter how much you rinse it.

The other property of natural shampoo that affects how well it works in hard water is that it often has an alkaline PH level. It is this PH level which is often why you might see people using acid rinses, such as a vinegar rinse, alongside using a natural shampoo bar.

Whilst there may be similarities in the ingredients that natural shampoo bars and other types of shampoo bars have, natural shampoo bars will commonly have oils and fats as their main ingredients. Look out for the following:

  • Sodium Olivate (olive oil)
  • Sodium Castorate (castor oil)
  • Sodium Cocoate (coconut oil)
  • Sodium Sunflowerate (sunflower oil)
  • Sodium Shea Butterate (shea butter)

What’s the difference between natural shampoo and regular solid shampoo bars?

The main difference between the two types of bar is the ingredients they use and their PH level.

What is most commonly known as natural shampoo are shampoo bars that work in a similar way to soap bars, using saponified fats to clean your hair without the use of any type of detergent or cleansing agent.

Solid shampoos that use surfactants will contain one or more ingredients to boost the cleansing properties of the bar. This makes them very effective at cleaning your hair, no matter what water type you use them in, and will do a much more consistent job of removing any dirt, product or mineral deposits that you have in your hair.

Depending on the bar you choose, surfactant-based solid shampoos will likely be PH balanced so that there is no transition phase and no need to use a vinegar rinse alongside them too.

If you want to choose a shampoo bar with a surfactant in it, look out for these ingredients:

  • sodium coco sulphate
  • sodium cocoyl isethionate
  • sodium cocoyl glutamate
  • decyl glucoside

Which is better: natural shampoo or shampoo with surfactants?

Natural shampoo is not recommended for coloured hair, as it can cause fading. Other than that it largely comes down to personal preference and the results you want for your hair.

As I’ve mentioned, my personal experience with using natural shampoo in a hard water area is that it can take more time (and therefore water) to achieve the results I wanted for my hair. Because of this, I prefer to use shampoo bars that contain surfactants as they are more user-friendly and I prefer the wash results.

Why some people don’t like SLS and surfactants

Perhaps one of the main sticking points with surfactants, particularly those like SLS (sodium lauryl sulfate), is that they can be petroleum-derived and synthetic (although there are many plant-based surfactants too).

SLS in particular can be irritating for some (not necessarily all) people’s skin and scalps and some people simply don’t like the results they get from washing with it.

A lot of the shampoo bars that we sell contain a plant-based surfactants that are commonly considered gentler than sodium lauryl sulfate.

We’ve found The Eco Well’s article on SLS to be a useful resource if you would like to dig deeper into the science behind surfactants.