Water and wastewater utilities can share emergency capabilities even further through state mutual aid agreements, such as WARNs. WARNs are intrastate networks of "utilities helping utilities" that can help respond to and recover from an incident affecting the water sector through the sharing of specialized resources and personnel. These networks are centered around a mutual aid and assistance agreement, which describes the administrative framework through which support is provided.

There are WARNs established in 49 states and the National Capital Region and their members consist of water and wastewater utilities – public and private, large and small. In many cases, WARN associate members include primacy agencies, state EMAs and water association representatives.

The benefits of WARNs are numerous. WARNs work to:

• Reduce the burden on state and federal response.
• Fill the gap between disaster onset and the arrival of aid.
• Ensure the right resources with the right skills are available.
• Enhance planning and coordination.
• Provide utilities with up-to-date emergency contact lists.
• Reduce administrative conflict.