Is filtered water really that important?

I'm about to start my next hydro grow, in my newly constructed grow box (pics coming soon). I used filtered water for my last grow but it was such a hassle. Tell me, is it really that important to use filtered water? It'll be ph adjusted no matter what water I use.

The thing is. Do you know what is in the water you plan to use ? Yes you can test the EC or PPM's but that doesn't tell you what is in your water. If you have been growing with say well water like my bro and it has worked for you many harvest then go with it.

I have county water with a ppm of 300. If I let it sit out open it will come down to 200 ppm's. What is left is chlorine that will not evaporate and floride ( google floride) and who knows what else. If you have been using well water on the farm to irragate all the veggies for generations your set.

You can test it out and try or die. Then you will know.

I don't walk on the lucky side of life so, I have to start at 0 ppm's and add back calmag plus to get what I want. To me the hassle is well worth the harvest.