An overview of the Geometric Network toolset
The Geometric Network toolset contains tools to create, manage, and run trace tasks on geometric networks.
A geometric network is a set of connected edges and junctions, along with connectivity rules, that are used to represent and model the behavior of a common network infrastructure in the real world. Water distribution, electrical lines, gas pipelines, telephone services, and water flow in a stream are all examples of resource flows that can be modeled and analyzed using a geometric network. With a geometric network you can perform various network analyses such as finding loops or circuits within a network or trace upstream or downstream to find the source of flow within a network.
Tool 
Description 

Adds an edgeedge connectivity rule to a geometric network. 

Adds an edgejunction connectivity rule to a geometric network. 

Creates a geometric network in a geodatabase using the specified feature classes, role for each feature class, and the specified weights with weight associations. 

Find Disconnected Features in Geometric Network 
Finds junctions not connected to edges for a simple junction feature layer. Finds edges not connected to any other edges for simple and complex edge feature layers. 
Rebuild Geometric Network  Drops and recreates the logical network index for the geometric network. If the geometric network is in an enterprise geodatabase and is versioned, the logical network will be rebuilt across all versions of the database. This tool will not change features in the network, no snapping will occur, and no orphan junction features will be created. 
Removes a connectivity rule from the geometric network.  
Removes an empty feature class from a geometric network. 

Sets the flow direction for a geometric network based on either the digitized direction or the source/sink settings in the geometric network.  
Solves the specified network analysis problem based on the flags, barriers, and specified weight properties. 

Verify and Repair Geometric Network Connectivity  Detects and optionally repairs a variety of connectivity and geometry problems within geometric networks. 