Arizona has some of the hardest water in the country.
Arizona water is hard almost everywhere, and in much of the state it is very hard. Most people know this in the sense that they scrub their shower doors more than their relatives in Oregon do. Fewer people have added up what it costs.
Hardness is dissolved calcium and magnesium, measured in grains per gallon. Anything above about 10.5 gpg is classified as very hard. Large parts of Arizona sit well above that, and groundwater in some areas goes considerably higher.
These minerals are not a health hazard. They are a plumbing hazard, because once water is heated or evaporates, they come out of solution and stay wherever they landed.
This is the big one. Scale in the bottom of a tank insulates the burner, so the unit works harder for the same output, and the steel runs hotter than designed. Arizona water heaters routinely fail years before their rated life. Every premature replacement is a bill you would not have had on soft water, and every month of running a scaled tank costs extra energy. See water heater repair & replacement for what that looks like in practice.
Scale narrows supply lines gradually. Cartridges and valve seats wear faster. Aerators clog. None of it is dramatic on its own; together it produces a house where "the pressure is not what it used to be" and where faucet, shower & fixture repair calls come round more often than they should.
Dishwashers, washing machines, ice makers, coffee machines, evaporative coolers - anything that heats or holds water scales up. Manufacturers' warranties assume reasonable water.
Hard water reacts with soap instead of lathering, so you use more of everything, and you spend real time cleaning scale off surfaces.
The genuine solution. Removes calcium and magnesium by exchanging them for sodium or potassium. Nothing downstream scales, because the hardness is no longer in the water. Needs salt topped up and a drain connection. water softener & water treatment installation covers sizing, the loop, and installation.
Sizing matters and is frequently done badly. It depends on your hardness number and your household's daily water use, which is why we test at the property rather than quoting from a catalogue.
These do not remove hardness. They change the crystal structure so minerals are less likely to stick to surfaces. Less effective than a true softener, but a reasonable option where softener discharge is restricted, where there is no drain, or where you do not want added sodium.
Filtration deals with sediment, chlorine and taste; it does not deal with hardness. Reverse osmosis at the kitchen sink handles drinking water quality. Most Arizona households that go this route end up with a softener for the plumbing and RO for the glass.
Flush the water heater annually. Have the anode rod checked. Soak aerators and shower heads in vinegar. This does not fix hard water, but it substantially slows the damage.
Before buying anything, get your water tested. Hardness varies significantly between - and within - Arizona cities, and on a private well it can be very different from the municipal supply a mile away. The number determines the equipment. Anyone quoting a softener without testing is guessing.
The honest answer is that it depends on how hard your water is and how long you plan to stay. If you are in a very hard water area and you have already replaced one water heater early, the arithmetic usually works. If you are renting for a year, it does not. We will test, show you the number, and tell you which of those two you are.
Call and describe what you are seeing. We will tell you whether it is a tonight problem or a Tuesday problem.