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How to use shampoo bars in hard water

Choosing your solid shampoo carefully is an important part of succeeding with using a shampoo bar in hard water. Not all types of shampoo bars work well in hard water due to a combination of the ingredients they use and their PH level.

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 fear not, we’ve listed some fantastic options for the best solid shampoo bars to use in hard water, that won’t leave your hair looking and feeling worse than before you washed it.

If you enjoy using natural shampoo bars and want to know how to get the best results from them in hard water, jump to the natural shampoo bars and hard water section, where we’ve suggested some of our favourite natural shampoos and tried and tested washing techniques.

The best shampoo bars for hard water

Sage Folk HQ is based in Norfolk, where we have hard water (and plenty of limescale to show for it). We’ve been through the transition period and have had great results with the natural shampoo bars that we’ve included in this post. But we also know that they won’t be for everyone, so got some equally fantastic solid shampoo bars that will work in hard water:

2-in-1 bars by Zero Waste Path.

2-in-1 shampoo and conditioning bars by Zero Waste Path | Available at Sage Folk

We love these 2-in-1 shampoo and conditioning bars by Zero Waste Path as they’ve been PH balanced to ensure there is no transition period necessary when using them, and so that they will work well in hard water. They’ve also been formulated with ingredients to help keep your hair soft and tangle free. Depending on your hair type, you may find that you don’t need to use a conditioner with them at all – reducing two plastic bottles from your routine with one bar!

We stock all four varieties of their 2-in-1 bars:

Botanical shampoo bars in tins by Bain & Savon

Botanical Shampoo Bars in Tins by Bain & Savon | Available at Sage Folk

We’re really excited to be stocking the Bain & Savon botanical tinned shampoo bars, as well as the natural shampoo bars that they create. Their tinned bars are made with gentle and biodegradable plant-based surfactants (made from coconut). We’re struggling to choose a favourite fragrance because they all smell so delicious (although anything with sage in it is going to be a winner in our books)

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.

Natural shampoo and its ingredients

What is mostly commonly known as natural shampoo – 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 – are not always suitable for use in hard water.

This is partly because 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 effects 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)

Solid shampoo that contains surfactants

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.

Our 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 you want from your hair, especially if you have been used to using regular bottled shampoos beforehand. This means it’s probably not going to be suitable for everyone.

Having said that, we stock natural shampoo bars because we also believe it’s completely up to personal preference. If you’re happy using natural shampoo, or you really wants to give it a try, we stock bars from lovely, independent UK makers.

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, whilst others 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 surfactant that is 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.

Natural Shampoo Bars and Hard water

If it’s your first time switching to natural shampoo, we would recommend reading our post on how to transition to using natural shampoo bars.

Some people find they can adjust to natural shampoo bars perfectly well, for others, you may need to experiment with a few different bars and techniques before you find what works for you.

The minerals in hard water can have a number of effects on your hair, all of which make it more difficult to use natural shampoo in hard water areas.

Firstly, hard water can make it more difficult to lather your shampoo, meaning you may end up using more product than if you were in a soft water area.

Hard water also makes it trickier to work the shampoo suds into, and out of, your hair because of the reaction that occurs between the natural shampoo and the minerals in the hard water. This reaction can form insoluble compounds which are particularly difficult to wash away – which is one of the reasons why you may be experiencing a greasy, sticky or even waxy feeling in your hair after washing it with natural shampoo. Essentially, you may be left with hair that feels like it hasn’t been washed at all.

Hard water can also ‘rough up’ the texture of the hair shaft, potentially making it seem more frizzy and tangled than when using a shampoo that contains a surfactant. This effect on the texture of the hair can also make it more difficult to get the natural shampoo lather out of your hair.

Your hair washing technique is going to play a crucial part in washing your hair with natural shampoo.

How to use natural shampoo bars in hard water

A downside to natural shampoo is that it’s more ‘labour-intensive’ (i.e. you’ll need to work harder to create a lather, distribute it through your hair and wash it out again) than shampoo bars that contain a surfactant. This is because surfactants foam up really easily and are highly effective at cleaning and cleansing hair in all water types. This makes them pretty easy to use and your technique is less important.

With natural shampoo bars, we’ve found it’s best to lather up the shampoo bar in your hand and work this lather over the crown of your head, repeating this process for the length of your hair, down to the tips.

Make sure to massage the lather into your scalp, to really help the product to distribute through your hair. Don’t let the fear of residue put you off from using enough of the product, using too little shampoo can make that feeling worse as you’re not getting enough lather in your hair to clean it.

Once you’ve worked the shampoo through your hair rinse, rinse and rinse – this is crucial to help get as much of the product out of you hair as possible. Not rinsing your hair thoroughly enough is a big contributing factor to that unwanted residue in your hair after using natural shampoo. Use that same massaging technique that you worked the product in with, to wash it out again. Pay attention to the hair at the base of your crown/ nape of your neck, this is often a problematic area for product build up.

Natural shampoo bars that we love

If you prefer to use natural shampoo bars, we have some really great options from Bain & Savon and Authentic House.

Solid shampoo bars by Bain & Savon | Available at Sage Folk





We currently stock the following varieties from the Bain & Savon range:


Authentic House solid shampoo bars available at Sage Folk





The bars from Authentic House are available in:

Things you can try to get better results with natural shampoo

If you’re really struggling with natural shampoo then please don’t feel disheartened, there are many reasons that it might not work for you and that’s completely ok. There are plenty of fantastic plant-based solid shampoo bars to try that might work better for you.

If you’d like to stick to using a natural shampoo bar in a hard water area, there are some methods you can try to get better results for your hair.

Try a vinegar rinse

Hard water can make the scales of your hair stand up, making it feel coarse and more prone to tangling and frizzing (particularly if your hair is also damaged in any way). This effect on the scales of your hair can also make it more difficult to get the shampoo suds into and out of your hair, which can also contribute to that feeling of residue or product build up after washing.

Using a vinegar rinse can help to smooth down the scales of your hair, making it much easier to wash away the shampoo suds. You can buy vinegar rinses or make them easily at home. You will likely need to experiment with the amount of vinegar you use and how often you are using a vinegar rinse as part of your routine.

It’s important to note that vinegar can be drying for your hair. Oily hair will most likely tolerate more/ stronger vinegar rinses, whilst dry hair will tolerate less/ weaker rinses (or not using a vinegar rinse at all).

Bottles of apple cider vinegar | ACV rinse for natural shampoo bars

DIY vinegar rinse

  • vinegar (raw ACV or white vinegar)
  • water
  • essential oils (optional, if you want to mask the smell of the vinegar a little).

To make your own vinegar rinse simply mix 1 part vinegar to 4 parts water in a bottle (you can add in essential oils to mask the vinegar smell if you wish). Increase the ratio of vinegar to water if necessary. Use after shampooing to help lift any lingering shampoo residue. If you really can’t stand the smell of vinegar, you could equally try using lemon juice instead.

Raw apple cider vinegar (ACV) is one of the more popular vinegar varieties to use in a rinse, as it retains much more of the natural goodness of the vinegar than other, more processed variants. We have heard that some people prefer to use white vinegar instead because they have found ACV to bring out a reddish tone in their hair with prolonged use, but I haven’t experienced this myself.

We found it best to use the vinegar rinse after washing out your shampoo. Pour it over your hair and massage it through like you did with the shampoo. Give your hair another really thorough rinse with water to remove the vinegar (and the smell) from your hair.

Remember, the vinegar rinse could be too drying for your hair if you are using it frequently over a prolonged period of time.

Baking Soda Cleanse

If your hair can’t handle a vinegar rinse, then using baking soda (bicarbonate of soda) can help to tackle the build up or feeling of residue you may be experiencing. Baking soda can help to lift the soap build up from your hair, it is also effective for lifting grease and even helping to cleanse the hair of chemical and product build up if you have been using synthetic styling products too.

Bicarbonate of soda in a glass jar | baking soda cleanse for natural shampoo bars

How to cleanse you hair with baking soda

Try mixing a pinch of bicarbonate of soda with a litre of warm water and soaking your hair with it before you wash it. Leave the mixture in your hair whilst you are shampooing it and wash it all out together, this way the baking soda can really help to lift out that unwanted soap residue.

Alternatively you could try sprinkling the baking soda onto your hair once you have lathered it up with your natural shampoo and working it in this way.

If you’re simply looking to cleanse you hair without shampooing it then you could try sprinkling the bicarbonate of soda onto damp hair, working it in and then rinsing it out.

Be aware that baking soda can make your hair more prone to tangling so you may wish to try a vinegar rinse or using a conditioner bar to help tease out those tangles.

If you’re interested in making the swap to other plastic free and natural products, why not read our guide to switching to natural deodorant.