[villagerfrog]

Several of my neighbors have cartridge style whole house filters installed in the garage by the inlet valve. We also installed this years back and we feel it made a great improvement. We use the PUREPLUS 5 Micron 10" x 4.5" Whole House Sediment and Carbon Water Filter Replacement Cartridge. The water tastes great due to carbon filter and have no residual on any of the faucets. I don't know if it reduces the hardness much but it does filter down to 5 microns. You can also purchase 1 micron filters, though more expensive, but we didn't think we needed to go that small. We get a 2 pack unit from Amazon for $30 and I replace them once we use about 20,000 gallons or roughly 6 months. I believe it would cost about $200 to have a plumber put in the assembly. It's interesting that you posted as I just changed the filter the other day. Take a look at the filter used for 20,000 gallons and the new one.