[esskay]

Really odd that it differs so close to neighbouring countries. Here (UK) I've never seen a Dishwasher without a salt hole, and there's often several well know brands of salt in the supermarket (no idea why, its all the same stuff).

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.

[wil421]

In the US you would install a house water softener that would soften the water when it comes into the house. It would only be used in areas with hard water. Our dishwashers usually use hot water rinses instead of cold water like European style ones, the hot water heaters will soft the water before it gets to the appliance.

[Mvandenbergh]

Ireland has very hard water for the most part so I don't think that'd be the reason.