Drain the pool - experiences - ideas?

The water is probably contaminated with the common chemicals

What exactly are the common chemicals? Chlorine breaks down in a few days. And nothing else has to be added.

Because of §54 WHG

Disposing of pool water correctly: The simplest option, namely infiltration on your own property, is not the right one and is prohibited. Pool water is wastewater and is classified as altered freshwater according to the Water Resources Act. Freshwater is altered by pool use in the domestic or other areas, e.g. by chemicals (chlorine), leaves, grass, sand, sunscreen, hair, etc., and must be disposed of via the sewage system.

By the way, filling via a garden water meter is therefore not permitted either.

When I look at §54 WHG, it says something completely different.

What is the common chemistry? Chlorine breaks down in a few days. And nothing else needs to be added.

I can't list anything further. See the post by WilderSueden.

When I look at 54 WHG, something completely different is stated there.

Yes, that was an explanation. I have highlighted the crucial part: Wastewater is 1. water that has been altered in its properties by domestic, commercial, agricultural, or other use and the water that flows together with it during dry weather (sewage water) If you pour in chlorine, it is definitely altered and therefore a case for wastewater.

If I didn’t have my own well in the dry weather of the past weeks, I wouldn’t be a fool and waste the good water into the sewage system. The lawn and all the flower beds would be so green and happy, they would get that much water.

Yes, that was an explanation. I have highlighted the crucial part:

Wastewater is 1.
water that has been altered in its properties through domestic, commercial, agricultural, or other use and the water that flows away together with it during dry weather (sewage)

If you pour in chlorine, it is definitely altered and thus a case for wastewater

As I already wrote, chlorine breaks down. And then the water is no longer altered in its properties (you must not remove the word properties from the context).

But yes, you are right, it is (incomprehensibly) forbidden.
Nobody really follows it though.