Scientific & Regulatory Support Information

The World Health Organisation

“No firm conclusions can be drawn concerning the possible association between sodium in drinking-water and the occurrence of hypertension. Therefore no health- based guideline value is therefore proposed. However, concentrations in excess of 200 mg/l may give rise to unacceptable taste.”

For more information, download our full report on drinking softened water.

Can I Drink Softened Water?

Yes… And it’s Even Considered “Wholesome”
However, we would always recommend a separate hard water drinking tap for taste preferences.

Is softened water suitable for drinking purposes?

This is a matter of personal choice. In the majority of cases softened water will be considered wholesome and is therefore safe to drink – but the answer is not always straightforward as there are some qualifications

In most of the UK, when hard drinking water is softened with a salt regenerated ion exchange water softener, the softened water is likely to comply with the Drinking Water Regulations. Provided the concentration of sodium does not exceed 200 mg/l, it would be regarded as wholesome and therefore considered safe to drink over the long term.

Water Supply (Water Quality), Regulations 2000

How much sodium is added to water during softening?

To keep below the 200 mg/l threshold for sodium, you can soften water containing up to 435 mg/l of calcium carbonate hardness, depending on the original concentration of sodium in the water supply, which must also be allowed for.

How many people drink softened water?

Millions!

During the 1920’s and 1930’s, water softeners started to be sold to home owners, hotels and many other businesses, to improve the taste of drinking water.

In the USA there is no myth surrounding softened water use for drinking purposes, and over 1 million people a year have a water softener installed.

Today, there are millions of water softeners in everyday use in American homes which are used for drinking water purposes. In some parts of the US, almost everyone needs one because the hardness of ground water, but millions of others are bought as a preference item.

There has never, in over 90 years of history, been a health related problem reported that was associated with a water softener.

What does softened water taste like?

Everyone has different taste buds, so whereas some people have reported the flavour of softened water to taste “pure and clean, just the way water should taste”, other people have described the flavour as “slightly metallic” and we have even heard it described as “like boiled water gone cold;- Flat”. Equally, many people cannot distinguish between the taste of softened water and that of hard water.

But there is a difference worth noting. If you sip a glass of softened water and roll the water around your mouth and over your tongue, the water will feel very smooth. If you then sip hard water, and roll that water around your mouth and over your tongue, many have reported a “fuller texture”. This heavier feeling in the mouth is in fact the dissolved limestone, or rock calcium.

Softened water makes a wonderful cup of tea, leaving no scum marks around the top of the cup or floating on the surface. Cooking with softened water will leave vegetables brighter and fresher tasting as no chalk residue cooks into the food. Making cordials with softened water will mean using less syrup as the flavour will be purer and fresher too, without needing to mask the chalky flavour and texture of hard water.

Can I use softened water for mixing baby feeds?

Yes you can, provided the softened water has a sodium concentration below the maximum of 200 mg/l for sodium. This level was adopted to ensure that the total sodium of the baby feed plus the water does not exceed 350 mg/l which is considered a safe level for infants.

I thought salt was bad for you?

In the USA, there is no limit on sodium in the National Primary or Secondary Drinking Water Regulations.

In the new, Third Edition of the World Health Organisation’s Guidelines on Drinking Water Quality, 2003, there is no sodium guideline. It only states that concentrations in excess of 200 mg/l may impart a taste.

It is the UK Department of Health that recommended limiting sodium concentrations to 200mg/l in drinking water for babies and those individuals on a medically-prescribed, salt-restricted diet.

There are some bottled waters containing over 1700 mg/l of sodium, and they are marketed as a health related benefit!

How can I find out how much sodium will be in my water when softened?

As a “rule of thumb” if the calcium carbonate hardness level of the water supply is greater than 400 mg/l, there is a higher probability that the softened water will be close to or above the sodium limit in the Drinking Water Quality Regulations.

Give me some facts and figures?

Let us compare the sodium content of a glass of London water that has been softened with that of other items in your diet:-

1 glass of water 25mg of sodium
1 glass of bottled mineral water 10mg of sodium
1 glass of skimmed milk 10mg of sodium
1 glass of whole milk 98mg of sodium
1 slice of white bread 350mg of sodium
1 tablespoon of tomato sauce 300mg of sodium
1 serving of cheddar cheese 820mg of sodium
1 serving of strawberry yoghurt 215mg of sodium
1 slice of apple pie 406mg of sodium
1 pork sausage 210mg of sodium
1 serving of tomato soup 667mg of sodium