I know one of the women here, can't remember who, maybe Marie? said they run the RO waste into their washing machine. Good idea if you can do it for sure. If you have a large basement, why not get a large holding tank for the waste. Then use it for laundry? Would need a pump though. Could basically isolate the Cold Water of the washer form the house system all together.

Other's, store and use for watering garden, washing car's etc. If you got a back yard pool.. I don't have any room for any of those idea's though unfortunately.

Personally, I don't see my hotwater tank running needlessly to be any greener then letting the waste go down the drain. Of course diy isn't just about money... But it should have some sort of benefit no? Would I go out and fix something that isn't broken? Probably not. Would I diy just for the sole purpose of complicating something that's easy and works flawlessly to begin with? Probably not. Am I gonna diy something that will just end up costing me more money? Again... probably not.

There is always room for improvement, I hardly see how a system that wastes more water than it produces is flawless.

How about a simple pressure switch and solenoid valve to control when the RO system is allowed to produce water?

A pressure switch on the hot water water line will activate a solenoid valve when hot water is being used.
The solenoid valve feeds the RO unit.
Waste water from the RO is fed into the hot water line before the water heater.

With this method waste water is only introduced when hot water is actually being used, such as laundry, dishwasher, shower, ect. This will not decrease the efficiency of the hot water heater and will not allow waste water to enter the cold supply. In addition an accumulator could be used on the waste water line which will allow some waste water to be stored before hot water is used and discharged more quickly when hot water is used.

Pretty sure I said WORKS flawlessly. I set a timer for 1.5hrs, turn the tap, done.

OK, so a system that wastes 4 times the amount of water than it makes WORKS flawlessly? I wouldn't use flawless to describe how such a system works.

If you're not interested in the idea I'm not sure why you would participate in the discussion.

Actually I drop the waste line into my washing machine, doesn't fill it up but as long as we keep the lid closed and use it in a day or two (aint hard in my household) it works out good. Perhaps you could pm me a list of topics and subjects I am allowed to post in? That would be most helpfull. When people disagree, changes are made. I'm no plumber but your suggestion of running ro only when the hot water tank has demand seems to make more sense then the original idea, so kudos to you, see what happens when people dissagree?

We use to sell the retro kits. If some are interested we can offer the kits again.

Im interested in zero waste or next to zero waste because it drives me to make a gallon of water i waste 4. Cant afford to drill a new well every three years. Nobody knows how long a well will last, i draw water from the tableland formation and im told that people have had these wells for years. As for diluting sewage water it doesnt matter. Once its gone its never the same. They use fresh water for fraccing oil wells and we're talking 320 m3 (320,000 L ) of water ( usually not that much) and once its used it gets disposed of in waste facilities. Its gone for good. Id like to make a gallon of water and have next to nothing for waste. My pump out runs every 2 days. Boooooo

You can post anywhere you want but it doesn't mean it will always be helpful or serve a purpose. Like I already mentioned a few times, the point here is to improve on a design that already exists and adapt it to better fit our needs. So far your comments have all related to the saying "if it isn't broken don't fix it" which to me seems to suggest you have little interest improving on this idea, hence my previous comment. After all your system "works flawlessly" so obviously you have no interest in improving it because if you did you would be contradicting your previous statement.

To disagree with something or just add another side is fine and benefits the process however I'm not sure that has been done because there hasn't really been any ideas put forth yet to disagree with.

The way to move forward with improvements is first done by figuring out what doesn't work or identifying the problem. As the system is currently available it won't work for, we know this already, hence the DIY approach. The next step would be to come up with new ideas on how to fix the problems or limitations and then we cycle back to the first step. If one continues to dwell on the first step and never move to the second it will never move forward. My goal here is to move forward.

How much RO water do you use on an daily average?