Ro/Di unit and your water bill

[millerman]

Hi all:

I was wondering on average, how much your water bill increased as a result of purchasing an RO unit. I picked up a 75GPD RO/DI unit recently, and I was amazed at how much waste water there was.

 

So the question is: Did your water bill go up significantly after purchasing an RO unit?

[AZDesertRat]

Maybe $5.00 a month.

It will depend on how much you make and how well your flow restrictor works. The standard waste ratio is 4:1 so its very easy to figure out how much water is consumed in a month. At 4:1 say you make 200 gallons of RO/DI in a months time, that gives you 1,000 total gallons of water consumed, 200 good and 800 waste. My water rate is $2.66 per thousand gallons of water and $2.12 per thousand gallons to treat the wastewater or $4.78 per 1,000 gallons total.

My bill is actually less than that as I have a MaxCap UHE ultra low waste RO/DI running at 1:1 waste ratio so mine went up $1.92 a month is all since I use much less for waste but thats a different story.

 

Things you can do is make sure the flow restrictor is not wasting too much, this is a common problem with many units since they are supplied with a non adjustable flow restrictor which may or may not be accurate. Test your waste ratio using a measuring cup and watch to see how it compares. You want 4:1 in almost all cases, if your tap TDS is very low, say 50 or less then 3:1 is sufficient but don't go any lower of you foul the membrane prematurely. Adjustable or capillary tube type restrictors are available starting at about $4 and are well worth the investment. You may not know this but waste flows increase dramatically in colder waters like in winter months.

 

Next is make sure the waste flow is stopping all the way if you use an autoshutoff valve, often they seep or continue running unnoticed. You may need a new ASOV or to add a check valve in the line which most vendors overlook but is a good thing to have for a positive shutoff.

 

Operating an RO/DI is not that expensive compared to the gas to travel to a LFS or grocery to purchase water plus the cost of the water. We have always used RO for drinking, icemaker and cooking too so get double duty out of the units. Buying all those cases of bottled water are a thing of the past, less plastic waste generation, less gasoline and a big cost savings in my pocket.

[millerman]

Operating an RO/DI is not that expensive compared to the gas to travel to a LFS or grocery to purchase water plus the cost of the water. We have always used RO for drinking, icemaker and cooking too so get double duty out of the units. Buying all those cases of bottled water are a thing of the past, less plastic waste generation, less gasoline and a big cost savings in my pocket.

 

Agreed

[nvdiz]

i use the waste water when I do my laundry

[Phixion]

As AZ said, $5 at the most... Most places such as where I live charge for water by the HCF unit (Hudred Cubic Foot) in which 1 HCF = 748 GALLONS. So if the rate is $1 per HCF (mine is about $1.12 a unit on a non-tiered price scheme) then figure for a properly setup RO/DI, you're spending $1 for every 187 gallons of usable water with the 4:1 waste ratio factored in. Beat THAT from any LFS and quality to boot! So if you W/C 5 gallons a week for a year, you'll be speninding ONLY $2 more per YEAR for fresh RO/DI for the actual water product. LFS is easily $2 per bucket of supposed RO water. Do that every week for a year, and you could be spending just $30 shy of owning your own system.

 

So anyways, you should see a ding (not a dent) at trhe most in your water bill, nothing noticeably significant. Remember, yard irrigation accounts for 70% of most house hold water usage, so your RO/DI system won't even come remotely close to touching that.

[AZDesertRat]

I figured in the cost of the wastewater treatemnt too which in our case is based on 80% of the water used in the winter months. Most municapalities charge for wastewater, some still a flat rate but most based on youur usage so you need to include that unless you have a septic system.

Even using my $4.78 per thousand gallons, thats only 47.8 cents for a hundred gallons or less than a nickel per gallon, thats darn cheap for a product that you don't have to lug home in a jug!

 

Phoenix bills by the cubic foot too but its easier to picture 100 or 1000 gallons than 748 cubic feet. Its actually $1.98 per unit or 748 cubic feet in the summer months and less in the shoulder and winter months but I used the highest rate period for illustrative or worst case scenario costs. All the other utilities I worked for over the years billed in gallons not cubic feet which is still easier for me to fathom.

[Phixion]

Yeah, it's hard to call with all areas charging different prices. The utility that I work for is one of the cheapest around I know of, for the first tier anyways off a 5 tier system. Unfortunately where I live we're flat rated on the waste/sewer so we're pretty much price gouged there if we use minimal water like I do. I have a grat picture at work though that we show customers to demonstrate how much 1 HCF really is. It's a man standing in front of a 748 gallon water tank, pretty impressive to see just how much water that really is.

[AZDesertRat]

My house is 32 years old. If I would switch out my two toilets for newer water saving type I would save much more with those than my RO could ever possibly use. They are like 3.2 gallons per flush now and the new ones are about a gallon, big difference when you consider how many times they get used by the average family in a day.

[Phixion]

Definitely. RO/DI uses far less water than people think especially if you have a 40g or smaller tank. But with what an LFS charges, plus gas to get there, blus the energy you use to lug buckets around, it makes no sense not to have your own system. I'm thinking it pays for itself in LESS than a year!

[kv2wr1]

It costs more to run my sprinkler system in a day than it does my RO/DI unit. I got a 150 GPD unit so I make enough water in 4-6 hours to last me 2-3 weeks. The unit will pay for itself in less than 6 months.

[Jakesaw]

My house is 32 years old. If I would switch out my two toilets for newer water saving type I would save much more with those than my RO could ever possibly use.

 

No way,

 

You'd just be flushing twice as much when you drop the kids off at the pool

 

[thewire]

So after factoring the membrane replacement every 2 years, + filters replacement...and if you do water change 2g every week for a year..how long before it pay for itself...let's initial investment is $100

[MikeTR]

LFS water...hmph... mine actually uses and admitted to using the tap water and treating it...

 

I tested 300ppm and I don't live very far from them

[AZDesertRat]

The pay off point will vary due to the cost of water and sewer rates if you own an RO/DI vs the cost of purchased treated water either from a grocery, vending machine, water store or LFS plus the cost of gasoline, wear and tear on your vehicle and your time it takes to buy and transport the water. These are all real costs.

Even leaving out gas and vehicle costs and your time, the average purchased RO only water runs between $0.25 and $0.50 and RO/DI is usally $0.75 to $1.00. It costs me less than $0.05 per gallon to make my own RO/DI so at a minimum its 5 times cheaper and more like 10-15 times cheaper if you buy it from the LFS. Thats using my highest summer wate rand sewer rates so in winter and shoulder months its about half that much. Doesn't take long to pay for a unit when you are saving $0.20 to $0.95 per gallon for every gallon you use.

If you only use 2 gallons a week you must have a tiny pico reef, even my 16G nano uses 4-6 gallons a week for top off and about the same for bi weekly water changes.

[AdrianBryce]

I live in an apartment that pays for my water. If they only knew how much water I was making