Live in 25 year old home. Water is from a well. Not that the water is bad but it is very hard. The holding tank for water was too small and the plumbing was all 1/2" so water pressure was never good.
Martin Water (Merv Keener) installed a new (larger) tank, re-used a water filter, installed a water softener and energy-efficient heat pump hot water heater with ALL NEW PLUMBING.
The new plumbing improved water pressure significantly and improved the existing site original nightmare. Installed shut-offs fore every device and labeled all piping.
Everything was done in one day and the site was cleaner than before the project.
There may be others who can do as good a job, but, there is no one who can do a better job.