now a quick spanner in the works...
all water is not the same from the dinos till now mates...
Water is 2 by hydrogen atoms stuck to one very popular oxygen atom..
So what you say, well we change that in every chemical reaction we do...
H2O plus many things ends up as a reaction and in some reactions off goes the H2 and the oxygen is trapped in a new compound... same goes for when we burn some hydrocarbon in air.... out comes CO2 and hey H2O... wow we just made brand new water...never drunk, pee-ed or sneezed before...
Even your body ex-hales out water and so does plants...So water is not constant on the planets, the majority of the atoms may be... but you can make water and you can destroy water back to it's elements... it happens in a simple wet lead cell car battery every time you use power. Thats why you top it up with distilled water....
And then again the planet looses hundreds of tons of water vapour to space every day that's up ... thereeeeeeeeeeeeeeeeeeeee high in the clouds, and by osmotic pressure etc,,, goes off to space.. ( just like on Mars...

)
a few billion years time, we probally have a dry waterless planet, but is it our job to speed it on it's way to it's dry final end, or help it stay a little more wet behind the ears for now...
ps, take a nice glass of fresh tap water and send it off for a quick microbe test and metals.... you will be shocked to see what you guys drink everyday. A recycling plant will stop many of the so-called nautral pollutants they feed your way everyday in your taps..
JMHO
Tony