No, a water descaler won't descale pipes. The charged water running through the pipes may very slowly dissolve mineral deposits and hold them inside the water, but it's a very gradual process. If your pipes do need descaling, it's much better to get a local plumber to descale your pipes.

Whether you need a license or permit for water softener installation depends on your location. Some municipalities require the installer to hold a plumbing license, while others may only require a permit and an inspection. In some cases, both a permit and a licensed installer are necessary, and some areas have no requirements at all. Often, only certified plumbers and electricians are allowed to pull the necessary permits. To find out the specific regulations in your area, you can contact your local building department. Alternatively, a local water softener installer or plumber will be familiar with the requirements and can typically pull the permits for you. Regardless of local laws, it is always recommended to hire a licensed professional to ensure the system is sized and installed correctly. You can use tools like Angi’s state licensing tool to verify an installer's license status.

If your water softener repair is fairly straightforward, like a simple filter replacement, then you can probably do it yourself with little risk. However, anything beyond a simple fix should be addressed by someone with extensive plumbing expertise to avoid costly water softener problems, like leaks. 

That said, even simple problems can be complicated to diagnose, particularly if your water softener is attached to a whole-house treatment system. So, unless you feel absolutely certain that the problem is an easy fix that you can take on yourself, it's probably best to hire a plumber to diagnose and fix the problem.

Hard water isn’t necessarily bad for you. In some ways, it’s good for you. If you’re deficient in magnesium or calcium, hard water can give you a mineral boost that you wouldn’t get with soft water. However, this is where the benefits of hard water pretty much stop. Hard water can cause many minor inconveniences and lead to costly, premature replacements of your water-using appliances.