If you use RO or distilled water you NEED CalMag Plus

I have 10 gallons of distilled with all my nutrients in it. I added two gallons of regular sink water assuming it has the calcium and magnesium. Is this a bad move?

Not necessarily, and most likely completely fine; however, now your nutes are at about 83% strength and assuming your tap water was ideal, your mineral levels are at 17% strength.

Yo I have a dehumidifier that is constantly running...is that water safe to use since it's humidity being sucked out of the air?

Yo maybe.
Do you see corrosion on the condenser? Is the catch container metal or plastic (metal bad, plastic good)? Do you know the conductivity of the water coming out (should not even register on your EC meter; if it does, you've most likely got dissolved copper or aluminum from the condenser)?
Still gotta run calmag if all that stuff checks out.

Sorry for the stupid question but Stinky mentioned taking your water to the "shop" and having it tested, I am atleast 70+ miles from the closest Hydro shop so where would the best place to go to get water tested without suspision and exactly what is the key to be looking for from the results? Silly me hasnt been able to purchase a meter yet but luckily I am on the 3rd grow and no problems so far just want to make sure I avoid any if possible.

If you haven't had problems yet, keep doing what you are doing.
The city sewer and water department should have a website where they post the actual test results on your tap water. Look at the TDS number.
If you are on a well, and suspect your mineral content is unstable, you are better off buying a meter. The cost of testing through a private lab can be high, and if you think you will need to have your water tested more than once, it's cheaper to get a TDS/EC/PPM meter.

Out here in the country we have agricultural extension office in each county. They will test water for free. I assume there is one in each county in the USA.

I disagree about the calmag. I've never heard of it and therefore never used it. I have discovered that using r/o water with Advanced Nutrients Sensi Grow/Bloom works out perfectly in a hydro setup and that is all I ever use. I never have to check ph or ec and have had much success. Lucky I guess.

Cal-mag plus will drop your water ph even at 2.5 mls per gallon and I don't even know how many ppm's that will get you to, so the more you need the more it's going to drop your water ph.

I just collect rain water than run it through a micron filter works perfect!