I blogged a while back about soft water, and the slimy feeling that you get from apparently not being able to rinse off soap with soft water.
Let me step back a bit and give you the whole story (and a solution).
A few months ago, we moved into a house just outside the city, which was on well water. We've always lived in the city, and I didn't know anything about hard or soft water. I grew up in Ottawa, where (as I've learned) the water is just a little bit hard.
What's the difference between hard and soft water? Mostly, calcium. Well especially comes right out of the ground without any filtration other than what you've got in your house, but even in the city, depending on the water treatment plant you've got, you may have more calcium in your water than you want.
There are fancy ways of measuring this but I think the best one is, does stuff build up on your dishes in the dishwasher? Do your nice clear dishes, over time, become cloudy? That's what happens to other folks around here that don't have a water softener.
The calcium in the water has some negative effects on the stuff in your house. Soap in general is less effective at cleaning in hard water than soft water, and the calcium builds up on shower heads, in your hot water heater, and anywhere else that water runs through. For these reasons, a water softener is a good idea.
This was all explained to me by a Culligan rep who showed up at my door shortly after we moved in, looking to renew the contract on our water softener. My first response was "Water softener? We don't need that.. you can come take it out" but she launched into this long explanation of the benefits of soft water, and came back with a testing kit to demonstrate how hard our water was (11 grains hard, which is apparently a lot). So we renewed.
A water softener uses some salt and some chemical trickery to remove the calcium from your water. Lots has been written on this process elsewhere so I won't go into it here.
But if you're new to soft water, your first experience with it may be like ours: Hey, why can't I rinse soap off my hands? You get some Ivory soap on your hands to wash them, you rinse under the tap, and your hands just feel slippery. It's like the soap isn't coming off.
The Culligan explanation for this is that it's because your hands are so clean, it's actually your skin rubbing against itself. You've never been so clean!
A quote from a Culligan dealer's website:
In soft water the curd never forms so your true skin feels soft and slick like you can't get the soap off, but the reality is that it HAS been rinsed off and you are just feeling your true skin for the first time perhaps.
And I bought it for a little while, but I was always suspicious. For example, if you get some other sort of greasy substance on your skin, like, well, grease, you can't rinse that off either. Is the grease also making my skin so clean? And toothpaste?
And, when my skin was slippery this way, I could wipe it off with a towel and it would go back to a normal feeling of clean. Maybe the towel was putting enough dirt back onto my skin that it was undoing the super-clean state that washing in soft water had given it? That didn't sound right either.
I spent some time googling, and found a chemical explanation of the process of softening water and from there, an explanation of the effect that has on soap that makes a lot more sense.
The sodium or potassium in soft water makes it much more unfavorable for the sodium stearate to give up its sodium ion so that it can form an insoluble compound and get rinsed away. Instead, the stearate clings to the slightly charged surface of your skin. Essentially, soap would rather stick to you than get rinsed away in soft water.
So what can do you do about it?
Use a synthetic soap! The chemistry that gives you this soapy feeling only applies to "soap".
Soap consists of sodium or potassium salts of fatty acids and is obtained by reacting common oils or fats with a strong alkaline solution (the base, popularly referred to as lye) in a process known as saponification. The fats are hydrolyzed by the base, yielding alkali salts of fatty acids (crude soap) and glycerol.
Synthetic soaps don't have the same chemical makeup.
Synthetic soaps aren't labelled "soap" since they aren't actually soap. If you're looking for a good soft water soap, look for something labelled something like "beauty bar".
I use Ivory soap because my skin is sensitive to something in scented soaps, so after making this discovery, I went looking for a synthetic soap that is also free of additives. And I found the Dove Sensitive Skin Beauty Bar.
A side by side test showed a pretty significant difference between showering with Ivory and showering with Dove.
So, if you're looking for a solution to why your water softener makes your skin seem slippery when you wash it, switch to Dove.