If you're drinking anything around a normal amount of water, extra is actually a little good for your kidneys as it helps them flush out things and not work so hard

Others have commented on water toxicity, and I thought it would be interesting to share this link

https://www.google.com/amp/s/www.nbcnews.com/news/amp/wbna16614865

This woman died from drinking so much water during a water drinking contest on a radio show. However, this was pretty extreme, she was chugging it back and it totally unreasonable rate. So I might not recommend for example trying to drink 12 gallons of water one day, because you might die. But unless you're drinking insanely crazy amounts, you're not at risk

However if you do find yourself continuously thirsty and drinking a lot more than seems normal, you might go see a doctor. Excessive thirst can be a side effect of poor kidney function or high blood sugar. Amongst other things.