DD and I have been discussing this because she recently had a UTI and was ticked off by our GP for not drinking enough during the day. This is because her job means she is often nowhere near a loo and she has got into the habit of not drinking when she grabs a quick sandwich for lunch.
I've been googling (as you do) and the recommendation seems to be 2 ltrs. but does that include tea and coffee etc?
I have never had a UTI myself but my mother, who wouldn't have known a glass of water if it threw itself over her, suffered them frequently in old age. They would send her completely doo-lally which is something I'd quite like to avoid. 
Her carers used to say that it was hard work getting the residents to drink water - not just Mum and dehydration was the reason for smelly urine 
I've always had a glass of water at lunchtime but other than that it's mainly tea and coffee etc., although I do drink more during hot summer weather.
My NY resolution is in the tap it seems.
Have you stopped buying papers?
Retiring and living frugally in money from downsizing after years of stress



