Bob, 

Is the issue you are having on the Hydrozone Map or on the Irrigation Plan? I ask because we separate the two into separate sheets so as to not clutter up either sheet with too much info. That being said, we have extended our irrigation valve call-out tags to include the hydrozone info so at a glance you can see what hydrozone a valve belongs to.

On the irrigation plans (typically at 10th scale or 20th scale), we too have locations where there can be several drip zones adjacent to each other. Like you, we make the drip boundaries a black line to separate adjacent drip zones that are part of a different valve. We also alternate the drip hatch pattern to further clarify that drip zones adjacent to each other are not part of the same valve. In the cases where one drip zone gets "cut-off" at a matchline from one sheet to another, it is usually not very difficult at all to differentiate from one drip zone to another or even being able to sort out what valve a drip zone belongs to from one sheet to another.

On the Hydrozone Map (typically at 40th scale to show the whole site on one sheet), we do not usually differentiate between adjacent valve drip zones as long as they are on the same hydrozone. That is, all the drip valves that are on the same hydrozone get the same hydrozone hatch. If a drip zone is on a different hydrozone, it gets a different hatch.

Adding a series of callouts across a valve's drip zone sound like more work than they are worth and so does making a linetype for each valve number. Can you please share some images of how you are doing it now so we can get an idea of how unclear it appears to be?

-CadMonkey