Depends on whats in your water, We were in the same boat regarding space. We wanted to fit a disposal, insta-hot,2 trash cans and a filter system in a 36" sink base. We removed a rather large RO system and installed a dual cartridge filter system. I can't say the water is as good but it is drinkable. We live in San Diego.... the water varies wildly in taste depending on the mix of Colorado and Northern CA water. Non RO setups generally filter chlorine and sediment but not minerals from my understanding.

I'm w/No_Name, we need to remove nitrates & nitrites and it seems we're limited to RO systems as they appear to be the only filtration systems that remove Nitrates & Nitrites...is that true? I haven't found any other type that does. But, they take up so much room if they're under the sink!

If they are our only option, they appear to be limited to around 15 gallons of filtered water or so a day...is that enough for a 4-person household...?

Should the whole house be on it? After all, we drink from both kitchen & bathroom sinks...but it seems a waste for showers, etc. and with a limit of 15 gallons filtered per day, we'll max it out.

And, I've heard that RO systems make the water acidic...

Any experiences w/removing nitrates & nitrites? Any other ideas/opinions?

Nitrates can be removed from water in two ways, through Anion exchange and Reverese osmosis. Do you have a Water softner for the whole house? If you do, you don't need a RO system you can just use a regular filter.

I have always wondered about filtering the water at my bathroom sink since you brush your teeth with that water. I currently keep a water jug with filtered water at my main sink for brushing my teeth though. I don't think any one has come up with a good solution for this. I have seen some people who have vanites in the bathroom add a filter faucet and a filter at the vanity.

Good luck!

No, no water softener. We've hesitated since hard water, in general, is actually good for you...all those minerals! The downside, of course, is that it can be harder on the plumbing (the house plumbing, that is!).

But, now that we know we have "high normal" levels of nitrates & nitrites, we probably need to do something about it.

the internet does say RO water can be more acidic..yikes.

Any comments on using just a single/dual stage filter system?

No_name, the pH of RO water is typically around 6 which is slightly acidic. However, if you live anywhere in the northeast, the rain that falls from the sky is nearly 100 times as acidic as that RO water. And that orange juice or Coke you're dinking is about 1000 times as acidic. So please don't lose perspective.

Then would it matter which 5/6 stage RO system to buy? I looked around ebay again and they all pretty much sell the same stuff. One thing I noticed with my old RO is that the water bill is high. That's one negative about RO, not sure if that's improved in recent years. Or any suggestion to add-on to ROs?
Currently there's a empty sink hole waiting to be filled :)

You might try looking for a zero waste RO system. That would at least help keep the water bill in check. I believe that a standard RO system wastes 3 or 4 gallons of water for every gallon of RO water produced.

Wow, that's a lot of wasted water, especially if you're on a well and the watertable is going down (too many vineyards using too much water). I'd like to have a water filtration system, but not at the cost of wasting that much water!

OK, let's get some perspective here:

1. We're talking about drinking water and possibly cooking water. A person might drink a gallon a day if they're trying to follow the "drink a lot of water" advice of some diets. You might use somewhat more if you're using the filtered water to cook pasta in. The amount of "wasted water" is pretty small--a few gallons a day. Similar in volume to a couple minutes in the shower.

2. The water is "wasted" only in the sense that you're paying for it, and sending it down the drain. And that waste is small--a few cents a year. Otherwise, it is in no way "wasted", as, say, one would waste gasoline by leaving your engine running. The water is water that came from the environment, and is going right back to the environment. It's not "used up" at all, it's just moved around a bit. So there really isn't any waste from an environmental sense.

I get my water filter cartridges from www.waterfiltersonline.com. You can get standard filter housings from them, at very reasonable prices, that take industry-standard filter cartridges. These filters and cartridges are used in huge volumes in commercial applications, like soda-dispensing machines and many other applications. There is also a huge variety of cartridges available. I highly recommend this approach over proprietary filter systems; as far as I can tell, the only advantage of the latter is that they make more money for the sellers.

As far as RO filters go, waterfiltersonline also carries those as well. I haven't researched them, but I suspect there are generic versions of those as well.

SolarPowered, the problem, though, when you're on well water is that while the "waste water" does go down the drain and into the septic system, there's no guarantee it's going back into the well. If you're in the middle of a drought (which until this spring we have been for several years), the water is absorbed by the surrounding ground before it gets down far enough to replenish the well. Yes, there are other sources of water also replenishing wells (streams, etc.), but all those levels have been down as well over the past few years. I still think using 3 or 4 gallons to produce one gallon of drinking water is wasteful if you're on a well.

Some of my neighbors' wells have dried up over the past couple of years--which is unfortunate since I'm afraid that means people are going to start lobbying for public water & sewer in an area that we're trying to keep relatively rural...public water & sewer means cramming 4 or 5 houses (McMansions!) on each acre of land and the loss of woodland & addition of pollution/traffic the higher density housing brings with it. Right now our part of the county is zoned 3 acres per house...with each house on 1 acre and the other 2 acres per house open/wetland/woodland in the "development"

Buehl,

Bummer about your wells. I can understand your concern then about being careful with every gallon of water--you're in a totally different situation than those of us on public water systems.