Housetraining takes time and patience. Puppies at 16 weeks have very little control and will need to urinate at least once every hour or 2. Puppies should be taken out every hour at least but it sounds like you are providing plenty of opportunity though by taking her out 2 times an hour. Also make sure you take her out when she wakes up and after eating. Feed your pup at regular times and don't overfeed. Avoid overly salty foods. Ensure that when she dose go out you always accompany her to the toilet area and praise her and reward the good behaviour with treats when she goes. You can also try associating a cue word with toileting. Until she gets better control it may be necessary for you to keep her in a safe area like the kitchen or bathroom or a room you can toilet proof with newspaper and plastic underneath.
The following site has some good tips:
www.maccvets.co.uk
The following site has some good tips:
www.maccvets.co.uk