R/O Water System Needed? I have water test results.

Ok here is the deal. I am wondering if I need a R/O water system for my DWC hydro system. I have looked over my county's water report and have posted it for you to look at. This is a test done by the county.

So if you could take a look see and tell me what you think. I have looked it over and it seems pretty low and I'm thinking I don't need it and get by with using tap water.

don5504 said:

Ok here is the deal. I am wondering if I need a R/O water system for my DWC hydro system. I have looked over my county's water report and have posted it for you to look at. This is a test done by the county.

So if you could take a look see and tell me what you think. I have looked it over and it seems pretty low and I'm thinking I don't need it and get by with using tap water.

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Those are the test results they are required to provide by law as a minimum. They also run what are called "in house tests" for undesirables. These are the results you want. They are tests for calcium, calcium carbonate, bicarbonates amd magnesium carbonates. You typically need to email them or call them for these results. Or take a water sample to nay pet store that sells salt water fish, or a store that sells and installs water softeners. The results are realted to drinking water but have little effect on plants nutrient water other than the chlorine level. With the turbidity level and the total carbon levels you like have water from a surface water source however so likely you will not need an RO filter (surface water typically is low in calcium and carbonates) but you should lower the chlorine levels by aeration over night before use.

I just want to say thank you for the information you sound very informed. And I forgot my password and info for my other account so I had to make a new one! Thank you so much again!

From what I know of fish tanks...they can measure the carbonate hardness for you at the fish store or you can buy the little kit. I think a tds meter would do just as well........mine is 250ppm from the tap and I've heard others at 300ppm that had no problems.....What I'd want to know is if they use salt as a softener............that would be my only worry, the rest is all stuff the plant can use as long as it doesn't react to your nutes and floculate(meaning they combine into an unusable form and sink to the bottom of your rez). I don't even age the water to remove the chlorine.......it's antifungal and antibacterial so it helps and will dissapate within a day anyway.....and chlorine is a micronutrient that plants use.....although very minute amounts.
The carbonates and calcium will give you issues in trying to Ph your solution...because that's what they're for...they buffer the Ph of the tap water to prevent algae blooms. Your nutes will also have a buffer to try to drive the Ph down so they're trying to cancel each other out.......so you end up adding Ph down to get to the Ph you want.....but until you neutralize the buffers in the tap it will always try to rise. I've just got to the point I don't fight it much....as long as I'm between 5.5 and 6.5 and the plants are happy...I don't mess with it...... I have an RO and I quit using it long ago.....watching three gallons go down the drain to get back 1 just didn't seem reasonable to me...and I didn't see any change in the plants...your results may vary......
PS......with that lead level.....I wouldn't let my kids drink it without filtering.....notice it says three sites exceeded the max allowable? Which 3? Mine? screw that!!!!

Lead levels are a result of the tin/lead solder used in residential and commercial water systems. They are not a result of water treatment or transport of water through water mains. Therefore do not use water that has stood in your home water lines for any length of time if you reportedly live in an aera of high lead concentrations. Water treatment plants must make a choice between add sodium carbonate to water to raise the pH so as to slow lead leaching "in homes" or to due to a build up of deposits of carbonate to coat the pipes. or to make the issue of lead in homes known so as customers can deal with it individually. The homes with the lead problems are typically homes built in the mid 50's to mid 70's when copper pipe was just becoming popular but the solder used was of a high lead content.

Never use water in the morning that has sat in your pipes all night. Always let the water run in the morning for a few minutes. Anytime the water has sat in the pipes for more than a few hours always run the water for a few minutes before collecting it for cooking, or drinking. It takes time for enough lead to leach into your water in order to reach dangerous levels. 6 hours is considered the limit normally for water sitting in pipes before lead levels exceed the MCL EPA established (maximum contaminat lelels).

RO filters, distillation or Carbon especially treated carbon must be used to remove lead.

There is also one other thing to consider about lead and that is in above groumd plants nearly all lead taken up remains in the root systems. Only approximately 1% of lead makes it into the above ground portion of plants. Your lead levels are very likely not at a level to worry about as far as using it for nutrient water. 1% of a top reading of the maximum reading of 59 is only 0.59 and the allowable limit for children is 15. So unless your water is nearly 30 times worse than the worse sample obtained you are fine.

Severely high levels of lead will cause a reduction in growth but that is at levels of over 200 ppm.

don5504 said:

Ok here is the deal. I am wondering if I need a R/O water system for my DWC hydro system.

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You'll do fine without, but fatman's right, the most important data you need (sodium, calcium) are not included in this report, bearing in mind that sodium/salinity is a much bigger problem than calcium (which is a necessary micronute, but can at times be excessive).

In a couple of decades of hydro growing, I've yet to see a problem induced by municipal tap water. Only folks on bore water with high salinity or sulfur content need consider any purification methods.

I agree that the OP's water test report omits information on dissolved minerals. However, I disagree that a TDS ppm of 40 is a problem- or even 200, though that's pushing it, as that much conductivity could make the difference between a nute burn or not, depending upon how hot you run your nutes. If you run at about 1000 or less, 200ppm TDS out of the tap is still OK.

Residential RO sytems deliver water fast enough as long as they are being used to feed a starage barrel as is typical. The problem with most home units is their typical rek jection t rtaes are worse. It is not uncommon to find home units that only reject 90% to 95% of the concentrates, while a good larher Dow Filmtech with reject 98% of concentrates.

Wow sold water systems for a living and you recommend GE Merlin. That is lame. Merlins are not bad units, they are k just pr urposely made in off sizes so that you must use their replacemment filters. Neraly every other RO system mnafacturer use standard sizes so you can use replacement filters and membranes from a vaireity of sources. Merlins cost more tp purchase and more to maintain, but provide nothing in the way of improvements for that added cost.

TDS readings provide no data as to what the minerals are or chemicals are that remain in the water. So for that reason it is typically assumed that it is calcium and carbonates. Even Luca's formula only runs a max of 215 ppm calcium at a EC of 2.72. 2.72 is quite a bit higher than commonly used (like double) so saying 200 ppm is fine sounds a bit extreme considering you will be adding that to the full calcium needs already supplied by the manfacturer. Vegetables such as tomatoes would however love the extra calcium., A reading of 40 is nothing to really worry about however. Between 50 ppm and 100 ppm I would use hard water Micro instead of regular micro. I would be cautious about tap water with a ppm over 100. You can however draw water from your hot water tap and run it through a couple coffee filters while it is still hot. That will remove the calcium carbonate formed from soluble calcium by the water being heated. It will b not remove the other carbonates however. It must be done when the water is hot as once the water cools it becomes soluble calcium again.

just want to say that my tapwater is running, according to my ppm meter at 800 ppm.

I know. I am embarassed to post this. lol.

But I am having pretty great results, in fact the best ever with straight undechlorinated city tapwater. Except for my lack of females in this current project I would say according to my almost perfect plants that I have arrived as a gardener. *snifs* pride.

I am however using the rocket scientist of nutes. GH three part with hardwater micro. I dont need to ph. I run the nute calculator according to the website calculator. I am not adding any humics yet or flora nectar but I plan to soon.

I do ebb and flow in rockwool and also in rocks.

I love it. When I switched back to hydro from organic soil I was sick to death of ro water and caring at all so I said it will be with the least effort and care I can come up with. I literally run gleefully from faucet to res for a refill. I measure ppms still but the rest is kosher.


I found shit in my water I still dont think are legal to possess in any state. Plants seem to like it.

However I have no comparison grow and proper care must do better.

This is fun, to finally be the guy that uses tapwater. Bghydro has a link on their site to get some pretty detailed water reports. I wish I had it saved. I did a post with it once. See, lazy. lol.

There are university research studies where they are growing long stem roses in NTF systems using straight raw waste water (sewage). Doesn't mean I would grow pot that way. The only major difference between HW and regular micro is a 20% reduction in calcium and nitrate. I suspect you are having a daily substantial rise in your pH that will only get worse as the plants start budding.

fatman7574 said:

There are university research studies where they are growing long stem roses in NTF systems using straight raw waste water (sewage). Doesn't mean I would grow pot that way. The only major difference between HW and regular micro is a 20% reduction in calcium and nitrate. I suspect you are having a daily substantial rise in your pH that will only get worse as the plants start budding.

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Fatman you ever check your pm's.

Only when the system notifies me that I have a PM.