Sometimes, dogs will stop drinking from their water bowl because they have had a bad experience. For example, if a dog's name tag on their collar touches against the bowl, it can make a loud noise that they find scary. They then develop an aversion to the bowl and do not like to use it. Dogs naturally prefer to drink from water sources such as puddles, which may be why she is accepting the water from the ground. I would suggest trialling a different type of water bowl (for example, if you have metal, try plastic) and placing it in a different area (in case she does have any 'bad memories' from the old water bowl). Consider using fresh rain water that has been caught from the outside as sometimes tap water can taste funny (particularly if the council have recently added something).
Can I confirm that she is not drinking or urinating any more than usual? If she is, this would warrant investigation.
With regards ***** ***** licking, can you think of anything at all that was spilled there by anyone? If her licking is focused in one place, it may be that there is something that smells interesting in that location.
Does she have any skin issues or itchiness? If so, this could be linked.
If not, we would consider that the licking is caused by nausea. Dogs are trying to settle their stomach. You may also notice other symptoms such as drooling, a reduced appetite or a grumbly stomach. Nausea is something that needs to be looked into and can have many causes. Typically we would do some basic blood tests to check things such as salt/sugar levels, liver function and kidney function.
Are there any other behavioural symptoms? For example, dogs that also do things such as 'staring into space', barking for no reason or pacing around the home at night time may have cognitive dysfunction.
Another consideration for floor licking would be OCD or obsessive compulsive disorder. These dogs constantly feel the need to lick, a behaviour that can be exacerbated by the fact that their skin feels itchy. However, as this is a new behaviour for her, OCD is less likely.
Is Misty an anxious girl? Fear and anxiety can drive unusual behaviours such as licking, which may be a way of her soothing herself. If the behaviour does seem linked to stress and anxiety, consider interventions such as daily calming supplements, an Adaptil plug-in and perhaps a behaviourist assessment.
What does Milly eat? There is a condition called 'Pica' that can cause dogs to lick and eat non-food items. We see this most often in animal's with deficiencies. Personally, I have seen this in dogs fed on home-cooked diets. If she is on a commercial dog food and does not have diarrhoea/vomiting, then this would be unlikely.
A final consideration would be that Milly is doing it for the attention. When she starts, do the people in the house react by paying her attention? Attention seekers will do whatever it takes to have people look and address them. If you are unsure if this is the case with Milly, you can easily check by recording her when no-one else is there. If the behaviour stops or reduces dramatically when alone, you have your answer.