Hard Water, Hot Water Heaters, & Water Softners

[Corbin H.]

Hello Everyone.  I just had my water and plumbing inspected in my 3 story town home rental, and I wanted to run the findings by he community to see what everyone's comments are.  The water heater is located in the attic with a potential to cause a lot of damage if it fails.

So, here in Houston we have hard water and according to my plumber extremely high in my case (Hardness: 25 Gr; Total Chlorine 1 ppm).  He has recommended a water softener (about $2.5K installed) and to replace the emergency shutoff valve on the water heater since it seems to be corroded.    

I have done a search here about water softeners and from what I have seen the majority here say that it is not recommended since you have to rely on the tenants to fill it with salt monthly and it is an added item that can break.

The water heater is about 8 years old now.  So, people that have properties and hard water, what do you do?  Should I get a water softener or just accept that I will have to replace the water heater sooner than most?  Also, what about tank-less water heaters, do they have longer life with hard water? Any other recommendations on how to handle this situation?

I appreciate everyone's comments.  Thank you.