Under Sink Reverse Osmosis

[jebmke]

We use bottled water for drinking and cooking. Our well water is safe enough but doesn't taste great.

Looking at putting in a R-O system under the sink but there seem to be a lot of alternatives - some have tanks, some do not.

Would be interested in any specific recommendations or other considerations as we look at various models.

Thanks

[daheld]

I don't have any experience with installing or using RO systems, but I'd say to consider whether you want to also dispense and drink water from the fridge. If so, you'll want to think about the installation location. If possible, it would need to go in a spot that will get you RO water to your kitchen sink and fridge.

[Cyclesafe]

Lots of experience with RO systems here. Had three over the years.

You gotta have a tank because filter throughput is too slow for "on demand".

Box store RO systems are junk.

I've been very happy with this one:

https://www.nimbuswater.com/products/re ... ierra.html

Compact, water-tight, easy to install. Get a TDS (total dissolved solids) meter ($15) to test when you need to change the membrane.

[lthenderson]

I have one at the last house and overall it was okay but there was a learning curve to it. For example, the tank relied on air pressure to balance the membrane against the water pressure and it was extremely difficult to set. Too low and the tank filled completely with water and didn't have enough water pressure to dispense. Too high and you couldn't store up hardly any water. We had a functioning range of less than 5 psi to get is set right. Eventually I bought a digital pressure sensor meant for setting race car tires that allowed me to set it just right. The other thing was that our tank was small enough that if we were having lots of people over for a party, we had to plan ahead and put some of the water in pitchers ahead of time because it couldn't keep up with demand. But once we learned these things and how to deal with them, it worked flawlessly for the ten years we lived there.

[chrismj]

We have a Hydroviv water filter installed under the sink and replace the filter every six months. They look at the water quality of your area and they say they can modify the filter to match your water.

I looked into reverse osmosis but it sounded like they weren't worth the cost/hassle. The upfront cost is pretty high and there is extra maintenance to be done. The water comes out very slow because of the filters. I think I read that the system could also stop working from lack of maintenance and it would be difficult to tell, as in water would still come out in an filtered state but the reverse osmosis action wasn't full taking place.

Maybe a reverse osmosis owner can counter/refute all of those points but that's what kept me away.

[hicabob]

These guys are good and have an informative website
https://airwaterice.com/

[Sandtrap]

We use bottled water for drinking and cooking. Our well water is safe enough but doesn't taste great.

Looking at putting in a R-O system under the sink but there seem to be a lot of alternatives - some have tanks, some do not.

Would be interested in any specific recommendations or other considerations as we look at various models.

Thanks

We have had various types of reverse osmosis filters under the kitchen sinks. Some were elaborate with tanks and multi filters.
Important considerations:
1 Placement. Make it easy to change the filters. Easy to place a flat pan under them to catch spills.
2 Parts. Buy a system that you won't have trouble finding parts and replacement cartridges.
3 Maintenance. Follow the protocols/timing for replacement, flushing, etc, and do lubricate the "O" ring seals as required.
4 Maintenance intervals will vary depending on the water in your area, hard water, etc.
5 Setup. Get the setup correct and redo it whenever you change cartridges. There is only so much water in the tank so be sure to have a large enough one to fill a large pasta pot, etc.

FWIW: we have had these systems for decades but switched to the ceramic cartridge Berkey countertop filter system for drinking water a few years ago. Less maintenance, simple, no chance of under counter leaks from a complex system.

j

[Mako]

In a previous house I had an iSpring system purchased on Amazon. Worked fine, my well had high nitrates and this removed them. As someone said above a tank is pretty much required because RO works slowly. And you want a line to the fridge if you have water/ice machine there.

It was an under sink system but the section below my kitchen was unfinished so I put it down there instead and just ran the lines up.

[seawolf21]

I'm very happy with
https://www.homemasterfilters.com/undersink.html

Their selling points are:

• Replace filter and housing to prevent leaks over time vs. competitor of replacing filter only

• Wider hose for faster flow

• Less waste water (brine) per gallon of RO water

• Higher production capacity

[rustymutt]

We use bottled water for drinking and cooking. Our well water is safe enough but doesn't taste great.

Looking at putting in a R-O system under the sink but there seem to be a lot of alternatives - some have tanks, some do not.

Would be interested in any specific recommendations or other considerations as we look at various models.

Thanks

I purchased a name branded RO for under sink installation. I did it myself. I was not happy with the amount of room it took up with the tank, tubes and 3 filter rack mounted to side of under sink cabinet. Total of 4 filters. With pre-filter, and then carbon activated filter, and I think it had 2 of them. The water out the sink was wonderful. Made the clearest ice you ever saw. Hard to get at, and I'm 6'5 I'll put the works in the basement next time, and plumb to it. I like room to work.

[MishkaWorries]

+1 for iSpring RO system. I installed one in our new house. Very easy installation and they have some YouTube videos to help.

The only installation issue was drilling the hole for the water faucet in the stainless steel sink. I was really concerned about making a hole in my new sink! I had to buy the right size drill bit. It takes awhile to drill the hole but no big problem and the end result looks really nice.

[bertilak]

I have a Culligan. No problems. I am on a yearly maintenance plan. They inspect, clean and replace filters once per year. After about 8 years, some fitting somewhere developed a slow leak and they fixed it.

It is a good idea to put a pan underneath to catch any drips and put a water detector in the pan. This happened only once, but it was nice to have caught it. (See https://www.amazon.com/Zircon-Leak-Aler ... 07QF19F9Z/)

[Phronesis]

Also on a well. We have very hard water. I've been using a system I bought on Amazon. I like it a lot. Several friends purchased on my recommendation and also like it. It comes with a couple set of filters and I change the filters every six months or so. 2 years of filters is like $80.

https://www.amazon.com/Express-Water-Re ... B00J2DGTD8

[jebmke]

Thanks for all the replies so far. Looks like some homework to do. Our water has a lot of iron in it and it seems like some units take care of iron and some don't.

[surfstar]

Ours was installed by previous owner/tenant. 5 stage RO type.
I've changed the filters once - with only 2 people we can get a couple of years on them. The one item I did install after some research, was a permeate pump - I believe this model: Aquatec ERP-500 Permeate Pump for up to 50 GPD.

Living in CA, I want to reduce our water use, but didn't want to un-install the softwater and RO system that were already there. The permeate pump makes your RO system more efficient with regards water use and also filter efficiency. Our water use is still much lower than neighbors, thanks to low-flow showers (sierra, via bogleheads thread years ago) and ultra low use toilets and despite a non-HE washer.

So, look into that pump - it wasn't much to buy and easy enough to install on an existing system, which would be even easier on a newly built one.

[sandan]

Ours was installed by previous owner/tenant. 5 stage RO type.
I've changed the filters once - with only 2 people we can get a couple of years on them. The one item I did install after some research, was a permeate pump - I believe this model: Aquatec ERP-500 Permeate Pump for up to 50 GPD.

Living in CA, I want to reduce our water use, but didn't want to un-install the softwater and RO system that were already there. The permeate pump makes your RO system more efficient with regards water use and also filter efficiency. Our water use is still much lower than neighbors, thanks to low-flow showers (sierra, via bogleheads thread years ago) and ultra low use toilets and despite a non-HE washer.

So, look into that pump - it wasn't much to buy and easy enough to install on an existing system, which would be even easier on a newly built one.

I've been doing some reading on RO machines to learn about this "Permeate Pump". Although it's widely recommended, it seems like people should check their water pressure first. I've read some directions that permeate's are recommended at 40 psi, but not above 60psi.

I also noticed that major external factors related to of a membrane's efficiency is feed pressure and water temperature.

This is a link to a chart on efficiency trade offs at an RO plant, but I think a similar principle applies for a home unit.

https://www.researchgate.net/profile/Ro ... -plant.png

The interesting thing is that filmtec membranes are rated for up to 150 psi.

[uaeebs86]

We had one under our sink that leaked while we were away on a vacation and ruined our cabinetry and flooring. Haven't had one since - my wife just uses the filtered water from a fridge. I drink tap water.

[enad]

We have a 5/6 stage unit with a 2.4 gallon tank and a permeate pump. 5 stages for drinking water and a 6th stage which adds some healthy minerals back in on it's own faucet used mostly for coffee. The outer canisters for the R.O. system last about 12 years before they start leaking so replacing them once every 10 years is a good idea. We have soft water which consists of a whole house GAC filter, then a Water Softener, then a post filter. Under the sink is a washable pre-filter 1st stage, a 2nd/3rd filter, then the R.O membrane and a polishing filter (there is a faucet here), then a mineral filter (and a 2nd faucet). The R.O. membrane lasts about 5 years and the other 3 filters about 26,000 gallons. The pre-filter last about 3 years and is washed on an annual basis. The mineral filter lasts about 18,000 gallons.