Can you drink water from a water softener?
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Part of our hard water guide
The limescale has gone. Now someone asks whether the softened water belongs in a cup of tea, a baby's bottle or the dog's bowl. What do UK officials say, and how can you check your own tap with a 20-in-1 test strip?
Short answer: The Drinking Water Inspectorate (DWI) advises keeping an unsoftened kitchen tap for drinking and cooking. Ion-exchange softeners swap hardness for sodium, adding by our arithmetic about 46 mg/l per 100 mg/l of hardness removed, against a 200 mg/l sodium value in England's Regulations. The DWI says not to use artificially softened water for baby feeds.
By Andrew Tomlinson, WaterKit · Last reviewed 29 October 2026
Can you drink water from a water softener?
Nothing we read bans it, but the Drinking Water Inspectorate advises drinking from an unsoftened tap. It says not to soften the kitchen tap used for drinking and cooking. The reason is sodium. An ion-exchange softener replaces calcium and magnesium with sodium, the drinking water regulations include a sodium standard, and a softener "may risk breaching this standard". The DWI adds that it may alter taste and smell, and that too much sodium can be a problem for people on a low sodium diet. Our guide to how a softener works explains the process.
The standard is 200 mg of sodium per litre at consumers' taps, in Schedule 1 of the Water Supply (Water Quality) Regulations 2016, which apply to water companies in England. Mains supplies seldom fail it. The DWI's Drinking Water 2025 report records 1 failure in 14,071 sodium tests in England. A World Health Organization (WHO) background document, first published in 1996, says most supplies contain under 20 mg/l and that domestic softeners can give over 300 mg/l, though much lower levels are usually found.
How much sodium does a softener add?
By our own arithmetic, about 46 mg/l for every 100 mg/l of hardness removed. The two DWI pages we read give no figure. The DWI says only that some softeners can add significantly to the sodium in drinking water, and cites the WHO drinking-water guidelines for that.
The sum is simple chemistry. Hardness is expressed as calcium carbonate, so 100 mg/l is 1 millimole per litre, and each calcium ion is swapped for two sodium ions of about 23 mg each. The table assumes a fully softened supply and ignores sodium already in the mains. Our portal does not say whether the strip's mg/L hardness is calcium carbonate, so read the 425 row as approximate.
| Hardness removed (mg/l) | Sodium added (our arithmetic, mg/l) |
|---|---|
| 100 | 46 |
| 200 | 92 |
| 300 | 138 |
| 425 (top step on our hardness pad) | 196 |
So fully softened very hard water could land near the 200 mg/l value, while lightly hard water would sit well under it. A real unit may leave some hardness in. Testing the hardness of your softened tap against the unsoftened one with a 20-in-1 strip gives a rough idea, within the pad's steps, of how much has been removed.
Can you use softened water for baby formula?
No, according to the DWI. It says artificially softened water should not be used to make up baby feeds, and points to the NHS page on making up baby formula. It also says too much sodium can be a problem for premature babies because their kidneys are not good at filtering it out of the blood.
Is soft water good for you?
The sources we read stop short of saying so. The DWI says there are no health-based guidelines for water hardness, and its hardness page says the UK drinking water regulations do not specify standards for hardness, calcium or magnesium. Where water companies soften water centrally, the DWI recommends keeping hardness at 150 mg/l as calcium carbonate or above, citing some limited evidence of a link between hardness and cardiovascular health. It also says artificially softened water may be aggressive to plumbing, causing copper and lead to leach. Our hard water health guide goes further into that side.
Why might your own tap differ from the area figure?
The 1 failure in 14,071 sodium tests describes supplies as sampled in England, not what comes out of your kitchen tap after a softener.
“If your kitchen tap and a softened tap are ever going to differ, it will be down to the kit in your own home, so I would compare the two side by side rather than lean on an area figure.”
- Where the softener sits. The DWI says fitting one just before the hot water tank or boiler is a more economical way to prevent limescale than softening the whole supply. A whole-house unit with no unsoftened outlet is the case the DWI warns about.
- How well it is looked after. The DWI says units not cleaned and maintained as the maker advises build up deposits and can create a breeding ground for bacteria. It names backwashing and topping up salt for softeners, and says a property left empty needs maintenance on return. Our servicing guide covers the usual intervals.
- How soft the water gets. The DWI, citing WHO guidelines for the corrosion point, says water of 100 mg/l as calcium carbonate or less is more corrosive to pipework, which could dissolve metals such as lead, copper, brass and nickel. For scale, the 2025 England report records 60 of 14,120 lead tests, 72 of 14,081 nickel tests and 2 of 13,785 copper tests not meeting their standards. Annex B does not link those to softeners.
How can you check your own taps?
Test the kitchen tap and a softened tap side by side. Fill a clean glass with each, dip one strip in each, wait 30 to 60 seconds and match the pads to the chart, or enter the colours in the free results checker. The table is our own reading of the chart steps. A strip result is not a legal sample, so the official values are yardsticks to read against.
| Check | Official value | What our chart can show |
|---|---|---|
| Hardness | No UK standard. DWI bands run from soft (up to 100 mg/l) to very hard (over 300) | Steps at 0, 25, 50, 100, 250 and 425 mg/L. A clear drop from the kitchen tap to a softened tap indicates the softener is working. The unit basis is unconfirmed, so the DWI bands are only a rough comparison. |
| Sodium | 200 mg/l at consumers' taps (Schedule 1) | The salt pad steps are 0, 100, 250, 500, 1000 and 2000 mg/L, read as sodium chloride. 200 mg/l of sodium is about 508 mg/l as salt, just above the 500 step. See the limits below. |
| Chloride | 250 mg/l indicator at the supply point (Schedule 2) | About 412 mg/l as salt, between the 250 and 500 steps, so the chart cannot place it exactly. |
| Copper | 2.0 mg/l at consumers' taps (Schedule 1) | Steps at 0.2, 0.5, 1, 2 and 5 mg/l, so 2 sits at the limit. |
Three limits matter. First, by our own reading the extra sodium from a softener comes without extra chloride, so it is not added as salt. We have not tested how the salt pad responds to softened water, so on a softened tap read the hardness pad, and do not take a low salt reading as showing the water is under 200 mg/l of sodium. Second, a copper reading at or above the 2 step is worth acting on, but the strip cannot read lead at the UK limit, so a clear result says nothing about lead. For that, see our lead pipes guide. Third, the optional rapid coliform bacteria test, read after 24 to 48 hours, is a presence screen and not a count.
The area figure is an average, and your own tap depends on the softener, where it sits and how it is serviced, none of which a water company figure describes. The hardness pad is the one that matters most here, since a clear drop from the kitchen tap to a softened tap indicates the softener is working, and a shift after a service or a change of salt settings would indicate the set-up has changed. The copper pad is the other, because a reading at or above the 2 step would indicate copper worth acting on. Best pack: 20 strips, enough to test the kitchen and softened taps side by side and again after a service or a change of salt settings, £5.99 (or £10.99 with a bacteria test), with free 2nd Class delivery on every order. See the kit
Your softened water questions
Can you drink water softener water?
The DWI advises keeping an unsoftened kitchen tap for drinking and cooking, so that is the tap it points you to.
Is softened water safe to drink?
The DWI does not give a yes or no. It advises an unsoftened drinking tap and says a softener may risk breaching the sodium standard.
Is soft water good for you?
The DWI says there are no health-based guidelines for hardness and cites only limited evidence on cardiovascular health.
Can you make baby formula with softened water?
The DWI says artificially softened water should not be used to make up baby feeds.
Can pets drink softened water?
In the sources we read, no UK official guidance covers this, and the DWI's advice does not mention pets. Our pets and tap water guide covers what we found for ordinary tap water, and a vet is the person to ask.
Sources
- Drinking Water Inspectorate, Domestic water filters and softeners (undated page; unsoftened kitchen tap, sodium standard, taste, baby feeds, premature babies, aggressive water, free water quality report, installer and maintenance advice, neglected units; read 29 October 2026).
- Drinking Water Inspectorate, Water hardness / hard water (undated page; hardness bands, no health-based hardness standard, 150 mg/l recommendation for central softening, ion exchange, low sodium diets, scale in appliances, aggressive water; read 29 October 2026).
- The Water Supply (Water Quality) Regulations 2016, Schedule 1 (sodium 200 mg Na/l and copper 2.0 mg Cu/l at consumers' taps; applies to water companies in England) and Schedule 2 (chloride 250 mg/l indicator parameter at the supply point; read 29 October 2026).
- Drinking Water Inspectorate, Drinking Water 2025, England, Annex B, compliance with standards (Table 26, sodium 14,071 tests and 1 failure, lead 14,120 and 60, nickel 14,081 and 72, copper 13,785 and 2; read 29 October 2026).
- World Health Organization, Guidelines for drinking-water quality, fourth edition incorporating the first addendum (overview page only, which the DWI cites for softeners adding sodium; we did not read the cited page; read 29 October 2026).
- World Health Organization, Sodium in drinking-water (background document WHO/SDE/WSH/03.04/15, first published 1996; most supplies under 20 mg/l, domestic softeners can give over 300 mg/l; read 29 October 2026).
- WaterKit, Water Test Kit (20-in-1 strip, 30 to 60 second read, optional rapid coliform test read after 24 to 48 hours, strips from £3.99, free 2nd Class delivery on every order) and results portal. The 46 mg/l per 100 mg/l figure, the worked table, the salt conversions and the strip-chart column are WaterKit's own arithmetic and reading of the colour chart steps.
Contains public sector information licensed under the Open Government Licence v3.0.