I get 4-1 ratio, 4 gallons waste for 1 gallon pure. Honestly, you can drink the waste. Waste is such a harsh word for a RO/DI unit. The waste can be used for plants in the house or honestly for drinking. My TDS on my faucet is 114 and it's in the 80s on the waste water line. It's purer water than what I would drink, so why let it go down the drain in my opinion.
75 & 100 gpd units across the board are typically 4-1, so 5 gallon bucket is really 20 gallons of water added to your water bill. Which when I was doing research, 20-30 gallons is a typical 15 minute shower on a standard shower head.
So if you are going through 20 gallons of RO/DI water a month, you are adding 5 - 15 minute showers a month to your water usage.
Still cheaper than buying your water from a LFS and not knowing what quality it is.
You can add an additional membrane to most units for around $60. This will take the waste water from the 1st membrane and instead of wasting it, it will send it through the 2nd membrane. This drops it to around 3-1. I suppose if one was in a real tight fix and going through TONS of water on their tanks then you could add up to 4 additional membranes and your waste water would be around a quart jar full for 5 gallons of RO/DI, but that would be a little ridiculous I think.
Solitude do you have more info on your sprinkler system set up? My buddy kc350twin is always looking for ways to use the waste. Most of the time it is really expensive and wonder if it is cost effective. Do your sprinklers use a booster pump? Thanks for the info.
Yes I think we need to raise awareness about water usage. Reef Builders has had many write ups on the subject. Als check out the Responsible reef keeping forum.
Some people use RO waste water for their ponds. My water into my RO unit is well over 600. It is city water and not from a well. I currently do not have a DI but will be adding one soon as my output from the RO is 24 and I want to get that number down.
I am thinking about installing a T in my waste line and running a line outdoors in the spring to water my tropical water/bog plants during spring/summer/fall using shut off valves on the two waste lines so I can make the water go either outside or down the drain.
Mine goes down the drain.... I live in an apartment and have no other uses and automate my ATO so I don't know when it's on. Also our apartment divides the total water bill to all 400 apartments so the cost doesn't change for me. I can't really see a cost effective solution to waste water for most people.