How To Install Navigraph more. In many communities hard water is a fact of life--mineral build-up is just something that happens. As common as this can be, long-term build-up creates plumbing nightmares that dramatically affect even the simplest home maintenance tasks. On This Page: • • • • • • • • Cost to Install a Water Softener If you are handy with tools and comfortable with written instructions, a water softener can be installed utilizing the do-it-yourself (DIY) method. Nevertheless, because of the nature of do-it-yourself projects, it’s best to have a professional install your softener due to the number of problems that can arise if additional plumbing issues occur. • DIY Cost – About $500 for a basic installation kit and unit.