When you place irrigation symbols, they seem to come in beneath (or under) the Schematic Irrigation Xref.
1. The best solution we've found is to assign a Transparency to the Schematic hatch layer.
2. If the symbols remain beneath the Schematic layer, type REGEN in the Command line and press Enter.
The symbols should pop back on top.
3. If the symbols are still beneath the Schematic layer, type HATCHTOBACK in the Command line and press Enter.
All hatches in your drawing, including the Schematic hatches, will be sent to the back.