While it's true that some of the water on earth has been peed out of animals, including humans, not all of the water has passed through animals and been peed out.
So while some of the water we use today and even drink today has passed through other animals and other humans and been peed out, the majority of the water has never passed through animals or humans or been peed out.
Water is constantly and continually recycled through the atmosphere and every water molecule on earth has indeed been peed out, sweated out or even consumed by living creatures including dinosaurs and other animals as well as humans, but not every drop of water has been through an animal or human.
Planet Earth has around the same amount of water that it did 4.5 billion years ago.
And through the water cycle, that water goes through, the water evaporates, condenses into clouds and then falls back down on the Earth and ground as rain.
Also because dinosaurs had roamed the earth for around 165 million years and had consumed massive volumes of water, it's also very statistically nearly certain that every glass of water that contains molecules has actually passed through at least a dinosaur.
And a single glass of water holds about 10 25 molecules and because there are infinitely more molecules in a glass than there are drops of water on Earth, the individual molecules that are in any drink of water or drink are almost guaranteed to have been inside of some animal previously.
The reason why not every drop of water has been through an animal or human is due to deep earth water and new water formation.
Water is actually constantly being destroyed and then reformed through metabolic processes in volcanic eruptions as well as plants and icy comets that enter the atmosphere, which means that tiny fractions of water are also reset occasionally.
And it's also estimated that vast oceans of water are also locked deep within the mantle and the crust of Earth, far beneath the biosphere and have never actually touched any living organism.
It's a great thought and is gross when you think about it.
But even the sewer water that goes through your toilet, sinks, showers etc and mixes with other peoples sewer is treated and then released back into the water cycle, where we use the water eventually and even consume it once again.
Or if you have a septic tank, the septic tank breaks down waste and releases the water out into the ground again, where the ground filters the water and it's returned back to earth and cleaned and we drink that water again.