Tap Water vs Distilled

Hey everyone,

I recently started two new plants that have been treated very similarly. Each plant is in the same soil, pot size, environment, etc. The only difference is that one plant was watered with distilled and the other was watered with tap water. I had predicted that the distilled plant would become nutrient deficient first due to lack of nutrients in the water. To my surprise the opposite happened. The distilled plant is flawless and the tap water plant is showing symptoms of deficiency. Since the outcome was different then anticipated I am very curious as to why this had happened. Any one able to explain the fundamentals here? Here’s a comparison image. Top is tap water, bottom is distilled.


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I would not read too much into this. Two plants (and are they even genetically identical?) is far too small a sample size to draw any conclusions about this.

Your tap water could have some characteristics that are detrimental to the plants, and maybe you want to invest in a water quality test. Depending on where you are, your water supplier may offer tap quality for a nominal fee. A water quality report would be more useful than a limited data set like this.


Each plant grown from seed. Same strain, same breeder. (unless there was a packaging mistake).

That doesn’t mean they’re genetically identical.

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Correct, they are not clones from the same mother.

Seed sellers, in my experience, tend to completely misrepresent the uniformity of their seeds. Cannabis creates a significant amount of variation during reproduction. Every stage produces a variety of genetic material, and those differences will compound to make broad filial diversity.

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But if I remember correctly, you mentioned pretty extreme pH issues a while back. Again, a laboratory test of your tap water might be a good investment. To generalize, I would not want my tap water to be out of the range of what is healthy for cannabis.

The rationale is that soil is pretty forgiving as far as pH goes. Nutrients remain available across a relatively wide range, compared to hydroponics. So if you’re seeing nutrient issues in soil, and pH is the cause, your pH must be way out of normal.

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Are you checking the PH of the water before input?
Distilled and RO water doesn’t have enough dissolved solids to be properly PH,d BUT those waters will take on the Ph of the soil so I no longer check my Ph using RO water.
Now tap water almost always contains enough dissolved solids where you can check the PH and can also change soil PH. Do you deal with the chlorine in tap before using? Do you check the PH?

With the limited info you posted it’s tough to say and as keystone said even if everything is the same the plants can be different during the grow

Are you using natural nutrients or man made bottled stuff?

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Most tap water is loaded with chlorine. After all, they recycle the sewer water into drinking water. Still nasty…old metal pipes can cause problems. Check tap water with a TDS meter as it maybe over the safe zone.

I’be found all kinds of things in the filter where I filter the water. Just recently I found orange colored chunks. I’ve seen green chunks. Where I say chunks imagine a extremely thin piece of a paint chip.

Where I live we do not fall under the Texas Water Board so who the hell k owns how bad our water really is other than a TDS meter check puts it around 267. :flushed:

I think I am having PH problems, but I haven’t really done anything about that this grow. This is my 3rd grow so I am still unsure what is a problem and what is not. PH of the water going in is around 7.5. It comes out at about 5.6 or 5.7. Based on any videos I have seen this is a big difference between input and output PH and is something I may want to be worried about. It was a loosing battle for 2 grows so I pretty much gave up trying to fight it. I am actually having better results this way lol.

I have never checked my pH and I’ve never had a problem and our tap water is bad. It actually has a brown color to it. I doubt I had the perfect pH levels for growing marijuana. :+1:

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Completely agree.


This grow, I have not done anything to address chlorine. The idea was to see what happens without concerning myself with various factors. Tap water TDS is < 100ppm. In my first grow, I had let the water sit out in an effort to allow any chlorine to evaporate. It is probably important to know that I have experienced these symptoms across multiple plants / grows. To me this suggests that I am doing something wrong. In fact, this distilled water plant is the healthiest one I’ve grown so far. The leaves are massive and healthy looking.

https://www.instagram.com/erdmundjanka/ for more examples.,


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Chlorine is bad for the plants. I can say that with 100% certainty. I actually tried this. I filled up a 5 gallon bucket for 1 week and the chlorine was still there. So I went with a water filter that takes out 99% of the chlorine and glad I did it.

I wish I had pictures where I can show you what the chlorine did. I had one plant not even 1 foot and it was one massive cola.

Chlorine can cause issues. Tap water at incorrect PH can cause issues with lockouts which would manifest as a variety of deficiencies.

If I had tap water under 100 ppm I would never use R/O again. Just let stand for 24 hours before use although a municipal water report is a good idea (worry about chloramines which do NOT dissipate).

This is why you want to know if chloramines were used (probably in this case)

@Myfriendis410 Oh I know my water is crap. No test needed. You can see it clearly. Hell this town isn’t even a town. Not even on the 911 Operators Grid. If you are having a medical emergency, you are S*** out of luck. :pensive:

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To clarify - just tap water that comes from a municipality, as they purposefully add it. Tap water from a well should not have it.

Not everyone lives with a well.

That is exactly my point. Not everyone utilizes municipal water.

Here’s a side by side of the two. Someone had suggested that this could have just been over watering. Thoughts?