Excellent topic!
Here in phoenix I could not grow anything for 2 years and lost hundreds to over a thousand or more on lost plants...until I purchased a Gard N Grow. That was the item which set all my gardening madness into motion.
Chlorine is used to kill microbiology and is really high in phoenix water supply. Calcium and salt are the other issues with the water and buildup in the soil, changing the PH to high in both soil and water. The way to deal with calcium and salt buildup is to deep water and flood the area. With chlorine water to flush the salts/calcium you then kill all the beneficial bacteria in the soil, and the roots get practically burned with chlorine and eventually starve the tree. With chlorine removed I was finally able to deep water while preserving the microbial activity in the soil, so all of a sudden I was able to not only keep plants alive, but they actually started growing.
With a sediment filter prior to gard n grow, the cartridges last for close to 40,000 gallons, so last a typical household a year. I have one on all my hose bibs and change them every 6 months. When they get close to the end of their life you can really start to see the difference that they are not working properly, and once you replace, you are back on easy street.