Answer: Each city and county has their own ordinances for gray water disposal but since you will be working outdoors and with outdoor plants (rather than washing dishes or clothes) there should not be any reason you cannot let the water drain right into your garden. I would imagine you could build a sink out of just about anything that holds water - wood, metal, etc. As for the frame, I think you'll find books in your library with step by step instructions and pictures. Or look up potting sheds on the internet. Most of these have sinks and you can get ideas from the pictures and drawings. Best wishes with your new project.
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