About symbolizing geometric network features
You can use symbology in ArcMap to easily identify enabled or disabled features, sources, or sinks in your network.
All network features can be either enabled or disabled. Enabled features allow flow to pass through them, while disabled features do not. This information is stored in the Enabled field in the feature class's attribute table. The values in this field are defined by a coded value attribute domain and can only be either 0 or 1. Features with a value of 1 for this attribute are enabled, and those with a value of 0 are disabled. By symbolizing your features using this attribute, you can quickly tell which features are enabled or disabled.
A junction feature can act as a source or a sink (or neither). When you build a geometric network, you specify which feature classes contain sources or sinks. Those feature classes have the attribute AncillaryRole that contains this information. The values in this field are defined by a coded value attribute domain. A value of 1 represents a source, and a value of 2 represents a sink. A value of 0 means that the feature is neither a source nor a sink. By symbolizing features using this attribute, you can quickly tell which junctions are sources and which are sinks.