I think that puppies are so little, and their systems are so finely balanced, that they absolutely must have access to water at all times .....
They need to keep their bodies hydrated, and if you remove their water suppy, their urine can become re-processed and very yellow and smelly, simply because they are having to conserve fluid in their bodies. This can lead to infections and other problems.
Trying to avoid having to mop up a few puddles as a consequence of keeping them thirsty all night is simply not a humane option - they are still babies and as such, should be treated with love and care, and not with any thought of 'what am I going to find in the morning' - what next - miss out the evening feed so that there is no poo either ??
They are only tiny once (unless you are a Breeder in which case you presumably know all about electrolytes and protein balances!!).