Underground natural gas storage fields in the American Gas Associations AGA East region have neared their capacity limits before each winter since 2005. Storage field utilization in the East has ranged between 87% to 92% before November of each year despite changes to market conditions. However, storage capacity utilization varies by region because of differences in weather patterns, types of facilities, pipeline constraints, proximity to supplies, and regulations.

Storage levels and available capacity for working natural gas, or natural gas that is used for withdrawal, respond to a different set of factors in each region:

via Trends in natural gas storage capacity utilization vary by region – Today in Energy – U.S. Energy Information Administration EIA.