Rain water is cheaper and collection is generally good for the waterways as it reduces runoff and erosion. Example: If you live in a suburb and get a major storm in the spring, I guarantee somebody has fertilized their lawn at the wrong time just prior. Everyone around me does and wonders why they have to mow twice a week in May. They also have likely applied a weed control. Pretty much everyone in the midwest has been hit by rain fairly well in the last few weeks. A lot of those toxins and fertilizers have run off into our waterways or downhill into someone else's garden (fortunately I live on a high point and use raised beds). The treatment plants in the midwest have yet to catch up on technology to deal with the extra runoff more pavement, houses, schools, shopping centers, and less trees equates to when you have a huge number of new developments. Fine by me. Our business thrives on overloaded motors at treatment plants (I sell motors and we perform testing on motors). Still, point is that rainwater collection helps in a number of ways and is just as good as RO. If you are in the south and the drought severely beats your community yet another year straight, collection in the spring will greatly reduce the amount necessary to draw from the tap in times of scarcity. Especially if you draw from an RO system which uses up to 3 times the water the tap does. My brother (lives just outside of Georgia in Beaufort, but goes to school there) said that last year there were people talking about banning full house RO systems for that reason and limiting them to under sink only. Makes sense. They were on strict water rations for pools and lawns. Why not go after a bigger problem common in some new high end housing developments? RO is very polluting and increases load on water treatment plants. It does nothing positive whatsoever for the water ways. They are expensive and increase the water bill. The water itself is great. Don't get me wrong. I just think it is definitely worth weighing the pros and cons. I have enough plants in the summer - soil and hydro - that they use more water than my family of 6 does in a month. If I used RO for the plants (we do for drinking), my bill would likely quadruple. It's not just the price of the RO system and filters. It's also the price of the tripled consumption one must consider. All the problems you described can also happen with water temp fluctuations or just too high of water temps all the time. I'm quite sure they can also be affected by the quality of light due to the changed rate of nutrient consumption under poor lighting and the chemicals secreted by roots under varying conditions. These are called root exudates. I did an experiment last year on artificial lighting versus sunlight and discovered many things about the nutrient solution along the way. I used the same solutions and water in both and found very significant differences in the fluctuations of one set over the other. The high quality light (sun) set had very low reservoir maintenance while the low quality light set all had reservoirs that shifted daily out of optimum ranges. I made sure that reservoir temps stayed within 5 degrees F of each other (that was the best I could manage). I wasn't trying to study that, though. It was an interesting side observation of the experiment I was actually running concerning the effects of lighting on yield and foliage. Sometimes the RO way is the only way. Apartment dwellers or those that live in those idiotic communities that have ordinances or HOA's against rain barrels due to aesthetics. Or maybe you live in a part of Colorado where collection is illegal (though that is being strongly fought). You say you no longer have pH adjustments but the plants look better. How? They must be feeding or they wouldn't look better. Feeding = changes in chemical composition in reservoir = pH changes. Especially with tomatoes. More so with heavy feeders with huge fruit like the Cherokee Purple. Am I misunderstanding you?

I have a very similar water system at my house. You probably should not water any plants with softened water. Even though it may have been doing ok so far with your lawn, the salts will build up in the soil over time. Some plants are more salt tolerant than others. Reverse osmosis is fine to water anything with. The RO process removes the salt. Sounds like your previous owners set up a very nice system. You should see what well water looks like unfiltered.

Agree with justalurker....adding a few things from my own experience.......... Most RO systems use air-pressure holding tank. When empty, those tanks are typically pre-pressurized at about 8psi. When full (about 2.5 gallons) they are pressurized at about 30psi. Your output volume at the dedicated tap will be governed by that pressure. My flow-rate with my previously-owned air-tank system was about .6gpm when full dropping to about 1/2 of that as the tank pressure dropped off. I've seen similar flow rates with neighbors' systems. This flow-rate is partially governed by line-size and valve-size being used. Refilling from empty against increasing pressure takes more time and wastes more water also. That's not bad, it's just the way things are. Some are better than others but they all do the same thing the same way. There are more systems becoming available that are designed to refill without back-pressure. They refill faster and waste less. Worth paying attention to in terms of day-to-day convenience, IMHO. FWIW.....I currently have Kinetico K5W which is pretty much at the highest-end of the home systems. The advantages of this system are 1) flow rate at the spigot is at household line pressure. At my 60-65psi line pressure, I get about 1.2gpm flow rate that stays level from full to empty. 2) Tank refills from empty (2.7 gallons) in about 50 minutes which is about 3x faster than previous air-tank model. 3) Tank refills with no back-pressure resulting in minimal waste as well as faster refill. These advantages are very worthwhile, IMHO, but they also come at a premium price. And, as justalurker said, I'm married to Kinetico. On the other hand, between softeners and RO's, I've now been with them for 19 years and their product and service performance has been exemplary. That performance and reliability I consider to have been worth the premium I paid. (I have no relationship with Kinetico other than as a retail customer.)

Way to spam the site @Ryan Stephen. An R/O unit is certainly possible for a small volume drinking water faucet. Other than that, I think you are out of luck. As others have pointed out, what you are suggesting would require the R/O unit to happen ahead of a separate water heater, The entire setup would be crazy expensive, and burn through filters and water. R/O water is aggressive if minerals aren't added back in. It has to be plumbed with plastic pipe. All of the plumbing and fixtures would need to be plastic. So here's a hot tip: I don't think you need a water filter as much as you need a computer filter. Deleting Facebook will remove a whole lot of contaminated thinking around fluoride in your water - not to mention virtually everything else. I'm being dead serious: when you think about actual damage and impact on your health and wellbeing - the misinformation you are getting is far worse than trace amounts of fluoride in your water.