Which Salt for Your Water Softener? How to Choose Well

Reading time: about 13 minutes

Anyone standing in front of the salt shelf for the first time sees eight bags that look alike and differ threefold in price. In the Google product results for this search term on 26 September 2026, bags from 8.99 to 29.60 euros sat side by side, from 15 to 25 kilos, with names like Broxo, Axal, Regenit and Soft-Sel. That raises exactly one question: do I buy the cheapest one, or do I ruin my two-thousand-euro unit with it?

An honest answer up front: PureAqua does not sell salt itself. We do supply the water softeners that need it, and we get this question on the phone every week. This article therefore answers it in full, including where you can buy the salt. There is no sales pitch in it steering you to our own bag of salt, because that does not exist.

What does salt actually do in a water softener?

The biggest misconception about softener salt is that the salt removes the limescale from your water. It does not. The limescale is captured by the resin beads in the unit, and the salt then empties those resin beads again.

That exchange immediately explains two things. First, why the salt has to be topped up: every regeneration flushes the captured limescale plus the salt used down the drain. Second, why purity matters. Everything that is not sodium chloride ends up in the resin bed and does not leave it on its own. The full process, step by step, is on our page about how a water softener works.

Consumption is therefore directly linked to the amount of limescale your unit captures. At PureAqua we see customers underestimate this: someone living in a hard-water area who uses a lot of water refills more than twice as often as someone with soft water in the same type of unit. More on that in the calculation below.

Softener salt, regeneration salt or salt tablets: the same stuff?

Yes. Softener salt, regeneration salt, water softener salt and salt tablets are four names in Dutch retail for the same product: pure sodium chloride, pressed or crystallised, intended to regenerate a resin bed. The confusion arises because every seller uses its own name. So do not look at the name on the bag, but at two things.

Purity. The better bags state 99.8 to 99.9 percent sodium chloride. That is the number that counts. The higher the purity, the less insoluble residue is left behind in your salt tank, and the less often you have to scoop that tank out.

Standard mention. Many bags refer to the European product standard for regeneration salt, usually in the form EN 973 type A. That is a supplier statement, not a seal of approval from a regulator, but it does indicate that the manufacturer fixes the purity and composition. A bag without any mention of purity or standard is not worth the risk for a unit that has to last for years.

What does not matter: the brand name. Broxo, Axal, Regenit, Soft-Sel, Limso and the DIY-store house brands all come from the same industrial salt production. As long as the stated purity is correct, you are buying the same product in a different bag.

Tablets, crystals or blocks: which shape suits your unit?

This is the only real moment of choice, and it is smaller than the packaging suggests. The shape does not determine how well your water is softened, but it does determine how the salt behaves in the salt tank and whether it fits in your unit at all.

Salt tablets

The standard for practically every household softener. Round or pillow-shaped tablets of about 2 centimetres, vacuum-pressed from pure salt. They dissolve evenly and leave little grit behind. Nine out of ten Dutch households can manage with these and do not need to think any further.

Salt crystals or granules

Coarsely broken salt instead of pressed tablets. Dissolves somewhat faster, which is handy for units with a small salt tank or a short regeneration cycle. Downside: crystals cake together into a hard crust more easily, the so-called salt bridge. In a damp cellar or a poorly ventilated meter cupboard, that is a real risk.

Salt blocks

Large pressed blocks, used mainly in compact units with a narrow salt shaft, including some of the AquaCell models. Advantage: you fill two blocks at once and are set for weeks. Downside: blocks only fit in units made for them, and they are generally more expensive per kilo than tablets. Always check this in the manual for your model.

The practical rule: take what the manufacturer prescribes, and do not switch shape halfway without first emptying and cleaning the salt tank. Never mix blocks and tablets in the same tank, because that creates cavities in which the water runs past the salt instead of through it.

Is the salt from GAMMA, Praxis, Karwei or Hornbach any good?

This is the most common follow-up question on Google, and the answer is more reassuring than sellers of specialist salt let on: yes, provided it really is softener salt.

In their garden and installation aisles, DIY stores sell two very different salt products side by side. One is softener salt or regeneration salt, usually Regenit or a house brand, with a purity statement on the bag. That is the stuff you are looking for. The other is road salt or de-icing salt against slipperiness, in similar 25-kilo bags, often cheaper. That stuff contains sand, clay and anti-caking agent and absolutely must not go into your unit.

There are price differences between a DIY store and a specialist salt dealer, but not in the direction you expect. At the DIY store you often pay somewhat more per bag, while online salt shops and water softener specialists become cheaper once you take several bags or a pallet at once. Anyone who fetches two bags once a year might as well use the DIY store around the corner and save the delivery costs.

Table salt, dishwasher salt and road salt: why they are not allowed

All three are sodium chloride, and yet none of the three belongs in your salt tank. The reason differs per type.

• Table salt: contains iodine and almost always an anti-caking agent. Those additives do not dissolve with it and settle on the resin bed. Table salt is also dozens of times more expensive per kilo, so it makes no economic sense either.
• Dishwasher salt: chemically the closest, because that too is pure sodium chloride. The problem is grain size and price: dishwasher salt is finely ground, dissolves too quickly and costs many times more per kilo. In an acute emergency it gets you through one regeneration; structurally it is a waste of money.
• Road salt: the most dangerous of the three, precisely because the bag looks the same. Road salt contains sand, clay and insoluble minerals that foul the salt tank, the injector and the resin bed. A blocked injector means a service visit, not a DIY job.

A fourth category you come across in shops is potassium chloride. That is a legitimate alternative which, according to the standard text for softeners, also simply works, and which is interesting for anyone who wants to limit the sodium in the softened water. It does cost well over double per kilo and you need somewhat more of it. You can read more about the trade-offs between using salt or not in our article on softening systems that work without salt.

The types of salt side by side

The price indications come from the Google product results for this search term, measured on 26 September 2026, and are converted to 25 kilos where the packaging differed. Prices vary per supplier and per offer, so use them as a range, not as a rate.

How much salt do you use per year? The calculation

This is the question for which you will find no worked-out answer anywhere in the Netherlands. The salt sellers settle for “that depends on the situation” and leave it at that. Yet you can simply calculate it, with three numbers you know yourself.

Number 1: your water hardness. Dutch tap water averages around 8 degrees German hardness. Waternet calls water hard only from 12 dH and states explicitly that the often-repeated claim by softener manufacturers that water above 4 dH is already hard is incorrect. Dunea uses the scale 0 to 4 very soft, 4 to 8 soft, 8 to 12 medium, 12 to 18 fairly hard and 18 to 30 hard. Your own value is on your water company’s website, by postcode.

Number 2: the conversion to salt. According to WMD, the legal range of 1 to 2.5 millimoles per litre equals 5.6 to 14 dH, which comes to about 0.18 millimoles of hardness per degree. The resin swaps every calcium or magnesium ion for two sodium ions, and sodium chloride weighs 58.44 grams per mole. At 8 dH that is 1.43 millimoles of hardness per litre, so 2.86 millimoles of salt per litre, or 167 grams of salt per cubic metre of water. That is the theoretical lower limit.

Number 3: your water use. Vewin works with a sector agreement towards 100 litres per person per day in 2035. Calculate with that, and a family of four uses 146 cubic metres per year.

The sum then becomes: 146 cubic metres times 167 grams is 24.4 kilos per year in theory. In practice it is higher, because a softener always doses more salt during regeneration than is chemically strictly necessary; how much more depends on the setting and the type of valve. Calculate with one and a half to two times the theoretical amount and you land at 37 to 49 kilos per year, or one and a half to two bags of 25 kilos.

All rows assume 100 litres per person per day and the conversion above. If you use more water, scale in direct proportion: 25 percent more use is 25 percent more salt. If your own practice deviates strongly from this table, that is a signal in itself. Structurally much more salt points to a wrongly set regeneration frequency or a leaking valve, and that belongs in the periodic check-up of your unit.

What does that cost per year?

With a 25-kilo bag between 10 and 21 euros, you pay 0.40 to 0.84 euros per kilo. A family of four at average hardness therefore comes to roughly 15 to 40 euros of salt per year. With fairly hard water and six people it rises to well over 90 euros.

Put that next to everything else and it is not much. According to Vewin, that same family pays an average of 2.71 euros per cubic metre in 2026 including taxes, so 146 cubic metres costs about 396 euros in drinking water. The salt is thus roughly 4 to 10 percent of your water bill. The purchase of the unit weighs far heavier: what that sum looks like is in our article on the total cost of a water softener, and the related figures on the water softener price page.

Two savings that really do something, and two that do not. What does work: buying several bags at once, because the price per kilo drops sharply on a pallet, and storing the salt dry so you lose nothing to caking. What does not work: switching to a cheaper salt with lower purity, because the difference of a few euros per bag disappears into extra maintenance, and dosing more sparingly than the manufacturer prescribes, because then the resin regenerates incompletely and capacity drops.

Refilling, salt bridges and maintenance

The rule of thumb is simple: never let the salt level drop below a third of the tank, and top up to about three quarters. Filling it completely is pointless and actually increases the chance of caking at the bottom.

That caked layer is the best-known problem and is called a salt bridge. A hard crust forms and stays in place while the salt underneath is washed away, so the tank looks full but the water no longer reaches any salt. You notice the result in the bathroom before you see it in the meter cupboard: the limescale stains come back while the unit seems to be running normally. Carefully break the crust with a broom handle, never with something sharp, and then check whether the level drops within a week.

Two things to include in the annual round. Scoop the insoluble residue out of the bottom of the tank once a year, even with 99.9 percent salt. And keep the room dry and ventilated, because moisture in the air is the main cause of salt bridges. Vitens points out that a poorly maintained softener can lead to bacterial growth with odour and taste complaints as a result, and advises buying only a unit with a quality declaration recognised by the Dutch state and an installation that meets the principles of NEN 1006.

That maintenance also determines how long your unit lasts; what else matters is covered in our article on the lifespan of a softening unit. And if you also want to get the limescale out of the appliances that already have deposits, you will find the approach in the article on removing limescale from a kettle.

What the salt does to your drinking water

A softener removes limescale and puts sodium in its place. That is not a side effect but the principle itself, and it can be calculated too. At 8 dH the resin exchanges 1.43 millimoles of hardness per litre for 2.86 millimoles of sodium, and sodium weighs 22.99 grams per mole. That adds roughly 66 milligrams of sodium per litre. At 12 dH it rises to about 99 milligrams per litre.

Does that stay within the standard? Yes, comfortably. Dunea gives the standard value for sodium in the Drinking Water Decree as 150 milligrams per litre, with taste complaints from about 200 milligrams per litre. Softened water of 8 dH stays below that with a sodium contribution of 66 milligrams, although the sodium that was already in it counts too.

That is precisely why installers often leave the cold-water tap in the kitchen out of the softening, or let the drinking water run separately. If you want the limescale out of your whole house and at the same time keep your drinking water as pure as possible, the combination is a softener for the pipes plus reverse osmosis for the drinking water. The membrane holds back the added sodium as well as limescale, plus up to around 99 percent of substances such as PFAS, microplastics and heavy metals. At PureAqua that filter system comes standard with a pure water tap, or you take it through the Worry-Free Pure Water subscription at 29 euros per month with 299 euros in start-up costs.

When you do not need salt at all

The most honest advice in this article: there are households that can skip the whole salt question.

The first group lives in an area where the water is already soft. Vitens already softens the water itself in many places before it reaches your home, and states that filtering or softening is not necessary for health. If you are below 8 dH, a softener of your own mostly brings costs and little noticeable difference. So measure your hardness by postcode first before you buy anything; the considerations are in our overview on choosing a softening unit.

The second group only wants tasty, pure drinking water and not a limescale-free shower screen. For them a softener is the wrong appliance: it puts sodium in the water and filters out no contaminants. A reverse osmosis system on the kitchen tap does exactly the opposite, uses no salt and only needs a filter change.

The third group is looking for a salt-free alternative because lugging bags puts them off. Such systems exist, but they work differently from a softener and the difference is bigger than the marketing suggests; what they do and do not do is worked out in the article on the downsides of softening. And anyone without a drain point in the meter cupboard runs into a practical problem that is described separately under installation without a drain point.

Frequently asked questions

Conclusion

The choice of salt is less exciting than the shelf makes you think. You are looking for pure sodium chloride of 99.8 percent or higher, in the shape that fits your unit, and the rest is brand packaging. DIY-store salt is fine as long as it is not road salt, and the price difference between the cheapest and the most expensive bag costs an average family at most 25 euros a year.

What does matter are the three things nobody tells you in the shop. Calculate your consumption instead of guessing: 167 grams per cubic metre at 8 dH, times one and a half to two. Keep the salt tank dry and break a salt bridge before the limescale stains come back. And remember that softening adds sodium, about 66 milligrams per litre at average hardness, so your drinking water deserves a different solution than your tap water.

If you only want limescale-free pipes, a softener with a bag of salt every six months is the answer. If you want pure, tasty drinking water, reverse osmosis is the route and the salt question disappears entirely. Drink different, and choose per problem the appliance that solves it.