The answer is to not use a repurposed water bottle. Further, use completely different types of containers for fuel and water so you can't mix them up.
Back in the day (the 1970's) when white gas stoves were popular (yes, the still are - I have one and it works great), there were aluminum fuel bottles. And, people generally used Nalgene bottles (or big metal canteens) for water.
Well, I knew somebody who thought that using the aluminum fuel bottles for water was really cool. But, he also used them for white gas, operating under the assumption that (1) he would buy different colored bottles (red for fuel, bare metal for water), and (2) anyway you could tell the difference by smell.
All was good until one night, while winter camping, he needed a drink of water. The 'water' and 'fuel' bottles feel the same on the outside. It was dark, so he couldn't tell them apart by color. And it was cold enough that the vapor pressure of the gas was really low, so an opened fuel bottle really didn't smell like anything. It wasn't until he had taken a nice big mouthful of liquid that he realized he had grabbed a fuel bottle instead of a water bottle.
Fortunately, he had the presence of mind to spit the fuel out before swallowing it. Unfortunately, the spray of fuel all over the inside of his tent raised other safety questions (Have you ever seen a down sleeping bag completely disappear in a giant ball of flame? I have, but that is another story.)
I only use Nalgene for water. I only use aluminum fuel containers for fuel. Never the two shall meet...