On July 9, 2024, the City of Mercer Island issued an urgent call for residents to conserve water as declining reservoir levels posed a significant risk to community supply and fire safety. Following an emergency alert, water consumption fell dramatically from 1. 2 million gallons to 787,000 gallons overnight, demonstrating the community's quick response. The city’s reservoirs are crucial for maintaining adequate pressure and volume, especially in emergencies like fires or water main breaks. Currently, the reservoirs are being fed by a backup supply line delivering only 2,500 gallons per minute, which is inadequate to meet peak demand.

The reservoirs must remain above 19 feet to ensure sufficient pressure for fire suppression, with levels considered full at 29. 5 feet. The city explained that a previous incident where a water main break drained over 500,000 gallons highlighted the vulnerability of the current system. Residents are urged to maintain their conservation efforts to help refill the reservoirs overnight. The city's proactive communication aims to ensure that both daily needs and emergency preparedness are met.