It's not common in the United States. Some all-in-one detergent packets might contain some amount of dishwasher salt, though.
Here's a nice map [1]
For a random location. Comparing the water hardness map with a population density map it seems that most are living in areas with soft water.
The exchange of the ions is driven be the difference in concentration between water and resin surface. It works both ways, but Ca²⁺ is preferred (=stronger bonds) by the binding groups (e.g. carboxylate salts). That's why a concentrated Na⁺-brine is needed to flush out the calcium ions.
Beads prefer Mg over Na but Mg prefers Cl over beads. So you can recharge with salt brine.
Or it might just be a concentration thing where Na / Mg ratio wants to be the same in the brine and beads. So you just give a really strong brine and most of the Mg etc leaves the beads.
If US folks are looking for this feature, it can be found on higher end Bosch dishwashers in the US.
I have very hard water and a Bosch benchmark series. The water softener makes a huge difference. I don't want a whole-house softener because I don't enjoy the feel of softened water in the shower.
We now have a Bosch dishwasher in another house in NY state. The water is not hard (it's from one of the Finger Lakes), and the dishwasher does not have a softener, but we like the brand. After reading this story we looked up how to tweak the rinse aid dispenser and turned it down from "5" to "1".
I actually do have a whole-house softener which came with my house. I installed a bypass valve so it does not feed the pipes in my home.
(Aside, and I don't know if they are still any good, but these dish drawers are really well engineered. Mine had some problems early on that were resolved by small changes in the design, but FP provided me the parts to retrofit my washers. They've been nearly trouble free since then.)
I was looking for a fridge-freezer specifically, considered Haier but went with Liebherr in the end - I like that (in terms of white goods/kitchen appliances) it only makes refrigeration units, other than where you use them there's nothing tying them together in why a manufacturer would be good at making them all really, makes sense to specialise in refrigeration, or dish washing, or gas products or whatever IMO.
According to the user guide, a water softener is recommended if your municipal water hardness is >250ppm which would be quite hard for municipal tap water.
In my region of central Florida the city’s water quality report shows a hardness well below 250ppm, Which you can divide by 17.1 to determine how many grains of salt to take that with.
[0] https://www.fisherpaykel.com/us/dishwashing/all-dishwashers/
I've never heard of either of these things before. Certainly not things on my, relatively fancy, dishwasher.
The water hardness setting determines how much the water softener tries to soften the water.
If the water isn't soft enough, it will leave spots on the dishes. Hence people use "rinse aid", so the improperly softened water would drip off before it leaves spots.
If the water is properly softened it contains no calcium etc. which could cause spots on your dishes.
I wonder if its based on average water hardness in the area. I'm in the north of England and our supply comes out of Buxton Springs (yep the same as Buxton bottled water) and is extremly soft so despite filling the salt it never asks for it to be refilled again as its not needed.
When I used to live in north London I'd be filling it up once a month as the water there is extremely hard - so hard that it'll kill your kettle within a year if you don't keep on top of descaling.
I'm pretty sure the majority of dishwashers sold here have salt compartments - I've never seen one without one.
Much of Ireland has very hard water.
But I think most people here in the Netherlands never set it up correctly and go for “all in 1” tabs. I never do, always set it up correctly. I do feel I need rinse aid to not have that nasty feel to the glasses.
Just small differences in water treatment and quality.
I know a few people who have a single outlet for osmosis water, I use a optional water filter in the kitchen outlet for drinking water.
But nobody I know is softening their whole water supply. Why soften toilet water? Why soften cleaning water? Garden water?
Well for the last 2 I guess it depends on how hard it really is
Softening cleaning water means your clothes come out - well, quite literally softer. And last longer.
It’s a great idea, given most municipalities have hard water.
Is the salt for doing a softening process that substitutes for a whole house softener if you don't have one?
We live in a place with hard water and have no softener in the house (you should see our electric kettle when we haven't cleaned it recently). Recently the accumulation of what I assume to be mineral film has gotten a bit noticeable on the dishes that go in the dishwasher.
The dishwasher is also 30 years old. Miele G 680 SC from 1992. Living in New York. Perhaps adding salt was more common in older models.
You might not have paid attention to it because your didn't know about it, but I don't think there are any dishwashers in Belgium that don't use salt, at least for the last twenty years or so.
2) IIRC, that house had a whole house softener.
I've only come across this in Spain so far. Never seen in Norway. But maybe I just haven't been paying attention. Then again, the water in Norway in :chefskiss:
rinse aid is for hard water. restaurants probably tend to not treat the water and the commercial dishwashers they use probably tend to not have a provision for salt. they operate very differently than your residential dishwasher.
So yes, completely unneeded if you have soft water. Most dishwashers don't have a provision for salt.
Also completely unneeded if you don't mind spots.
This is the real key, modern dishwashers have so many limitations in an attempt to reduce water and power usage they do an awful job. I wish there was more information on how to disable these features.
I never use any, and my dishes are completely spotless. 30 years old dishwasher, super hard water.
Specifically, you should:
- always fill the salt of the dishwasher's water softener once it's empty. It cannot soften the water if it doesn't get cleaned by the salt. If the water is not softened you will get spots. EDIT: Apparently US folks often have dishwashers which don't soften the water. Ugh. In Europe I haven't even heard that such a thing exists! :|
- configure the dishwasher to your water hardness.
- do NOT use detergent which is advertised as "you won't need salt". This is garbage for lazy people. It cannot properly replace the water softener. Think about it for a moment: The detergent is meant to fully dissolve during washing so you won't have it on your dishes after the final water cycle. The only way it could affect the softness of the water in the final cycle is if it did NOT fully dissolve in time. So there are two factors to be optimized which contradict - stay long enough to soften the water, but not long enough to leave remainders on the dishes. It will never work properly.
- This is not related to rinse aid, but you should know it: Clean the sieve regularly, at least every week. It will get ultra nasty with gunk if you don't. If you have no time for cleaning it, buy a second one, switch them once one is dirty and put it among the dishes so the dishwasher washes it like a dish.