I would not use a water bath for those vegetables. Anything that is low acid, which all of these are, should not be done in a water bath-they should be done in a pressure cooker, else there is a chance of botulism. Since I am afraid of pressure cookers, I solved the problem by freezing low acid veggies. But, for things that can be done in a water bath, I wouldn't see any reason not to reuse the water. As far as time-it's best to check either with a canning book or in the documents that come with the jars or lids to find out the recommended times for each type of vegetable or jam.