How does Pothos grow in only water?
It is not possible, that a plant grows without any nutrients. Magnesium for example is needed in every chlorophyll, so there is no photosynthesis without magnesium. Another point is that plants can not get nitrogen from the air, so they have to get it from the soil and nitrogen is present in every amino acid, which build the plants proteins. Proteins are essential for every living organism. This are only two points and there are many many others why every plant needs nutrients like nitrogen phophorus, magnesium... 

If it seems that Epipremnum aureum does only need water, maybe the plant gets its nutrients from a place you don't expect. Maybe the water is contaminated. Are there leafs falling into the water for example? Another possibility could be that Epipremnum aureum stored a lot of nutrients before it got only water but this won't last for ever. 

I read your comment, thats why i think the nutrients have to come from the water. Additionally I found this publication about Calcium Deficiency Symptoms of Epipremnum aureum 

I think you know that tap water or rain water isn't pure H2O. We just measured the tap water in Cologne, by ICP-MS. This is no official measurement, and we measured only once but I think its nice to see whats else in tap water.     Unfortunately we couldn't measure nitrogen, because normally the machine is used for plant extracts and there would be to much nitrogen. 

Maybe your Epipremnum aureum gets enough nutrients from the water, I don't know if this is possible and how often you change the water.

Your pot could also be a source for nutrients if its not sealed up. 

In conclusion the answer is that in general it is not possible, that your plant grows without nutrients. So there is a source which can be only detected by yourself, because you know the exact conditions under which your plant grows. I hope I could give you some hints.