Water pollution even with a filter

[JPLab]

So yeah, as soon as I got the filter, I installed it and dumped the "clean" water back into the ocean, or so I thought. Somehow it still started polluting it. I moved the dumping of the filtered water in a pit I built, still, pollution is spreading where I used to dump the water. Am I missing something? Pretty new to the game. Any help appreciated thank you, haven't found anything about water pollution with waste filter in the forum.

[SLG-Dennis]

The filter does not filter all pollution. You might also have air pollution around that will cause ground pollution as well.

[JPLab]

Ahh thank you, didnt see your answer :). Remade my piping so it dumps into a pit instead. The water pollution stayed stable for a day or two after removal of the water dumping into ocean and then started fading over about 3-5 days until water became clear again. Really well made simulation, I was amazed. And yes, I did have a coal generator next to water too that I removed at the same time :). Hope this info can help someone else in the future, and keep the good work going on this game devs!

[Erke]

Originally posted by SLG-Dennis:

The filter does not filter all pollution. You might also have air pollution around that will cause ground pollution as well.

Can the filter be daisy chained?
Meaning does the water get even cleaner if the first filter output is connected to a second one?
Would like to know the mechanics behind this before I invest time and effort into it...

[SLG-Dennis]

No, that has no effect. There always will be a slight pollution left, but that shouldn't have any real consequences if you're not around with twenty of them. In most cases this happens it's actually caused by the air pollution dropping down in biomes with medium or higher rain simulation, as typically workbenches that cause air pollution are near filters.