No more than two or three, preferably two. Use bold face and a larger font size for such things as headings. Just be sure that your font is easy to read - stick to basics like helvetica, arial. You can italicize a few words for emphasis, if need be, but don't get carried away.
Follow the old rule: KISS - Keep it Simple Sir

There is no true water less toilets.. However there are some "waterless" toilets that require very little water. Basically it is a toilet, collector, and pump. Once the toilet is used.. the waste is vacuum to the collector. Once collector is full it is pump to the sewer drain, at this point all system will require water to flush system to city sewer.. This is based on city sewer connection.
But this is not perfected yet so i would go with the waterless urinals..

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