It's the first time I own a dryer.
When I poured out the water it has collected (a few liters per run) I quickly tested the EC and pH and found out, that it is almost identical to the one made by my reverse osmosis filter!
No wonder, since the dryer is basically just a big distillation machine.
Thats super neat. It will save me a lot of work filtering tap water.
I will collect it from now on and use it for watering my plants.
Why does it matter?
Plants really don't like tap water. Even in a country like mine, where no chlorine/ fluoride/ whatever is added, the dissolved minerals cause trouble. They will build up over time and make nutrients unavailable, even if you adjust the pH.
The buildup and nutrient lockout will harm the plants a lot in the long term, and you will have way more trouble checking and correcting EC and pH.
Please be aware that that water can contain a lot of particles out of the clothes. It's better with a heat pump dryer as that has a better air filter to protect the condenser.
Also I recently fought some smell in my dryer by first spraying some diluted isopropyl on the condenser and then letting it dry out completely before closing up the maintenance hatch again.
I do believe bacteria can grow in the humid part where condensate is being collected - for a heat pump dryer even more so due to being warm but not hot.
When my daughter washes she's using fabric softener when washing - and I can smell that in the water collector after she uses the dryer. So the softeners perfume definitely is in the condensate.
But yes, I use it for plants, too. But (due to the particles) never in the clothes iron.