Exterior Water Features

IMO, the intent of the credit is isolated to irrigation... which is water put on living material (by an automated system usually) that returns to the earth. That would mean that water features are exempt from this point. Keep in mind LEED doesn't anticipate all situations, and exterior water features can be an important part of dealing with natural cooling in certain climates... so outright fountains are neither good nor bad. If there's an opportunity to use a non-potable water source for the water that's great, just keep in mind that reducing water usage for irrigation (by possibly using that same water... assuming rain water harvesting or condensate harvesting) should come first.