had this problem for a while now?
been to the vets and nothing can be found to be wrong,
this bitch i have will lick and lick her top of her feet and legs till the hair is sodden
we stop her from doing it as we think it is habit and that she was allowed to
do it before we got her, she does not lick them till they are red or sore that i have
known some dogs do but it is like it is comfort to her, she can do it when she comes
out the rain, off a walk,when it is hot, when it is dry, she may not do it for a couple
of days and then off she goes again anyone had this problem and did you cure it
by just making them stop when they started , she has nothing in her paws, her nails are short
it is such a puzzle to us

I really don't have an answer to help. 

But looked at the title, and came on to say that my Border Collie does this.  Then opened the thread, and realised that as it is my legs he's licking when I am stood at the sink, it isn't relevant. 

Shows you why the written word can be misconstrued!  :-)

LOL

Is it after activity?  It might be pain or low level discomfort that is difficult to diagnose.  You could talk to your vet about giving pain killers for a short period of time to rule it out.

If it's habit ideally you want to identify what it is that gives her pleasure - is it the comfort to her legs and feet, or is it that she enjoys licking?  Try giving her a swap for the oral response, like a soft toy or chew.

If all else fails distraction is generally the best option anyway so give her something else to do :)

no not after activity, she could be lying around and not doing anything and then start the licking and sucking at her feet and all across the top of her legs think we may have  to just keep distracting her

My Jozi used to do this whenever she was bored, sometimes in the car perhaps a little stressed on a windy route.

It started when she had to wear a buster collar when she had an eye ulcer, so ti was a displacement activity, and she used to really glob on the one foot (my breed are not drooly dogs), this did discolour the hair.

I found if I washed it with clean water as soon as I found her doing it it, *cool boiled water applied with cotton wool), it stopped the discolouration.

I would just tell her to stop as soon as I heard the horrible slurping.  She did it sporadicly, sometimes not for months.  She is now 13 and hasn't done it for years.

It never got to the stage of causing damage to the skin, as my breed have thick hair.

Interestingly JeanSW she is the one of mine who loves to lick my feet and legs (expect it would be anyone who would let her)

My Border Collie Megan, now 13, has done this all her life . She also likes licking me and leather bags. We've just accepted it as a Meggie thing and she hasn't damaged herself in any way. She's otherwise well except for age related degeneration -like me !

I would suspect either low level pain, or stress/boredom.  Saffi does it because of her arthritis pain, as did Soli - but Phoebe sometimes will get a little licky and it's stress relief for her.