HB 516 requires public water systems in unincorporated areas of certain counties to notify local fire departments about water service interruptions affecting hydrants used for fire suppression. For planned interruptions, notice must be provided in advance, and for unplanned interruptions lasting three hours or more, notice must be provided within 24 hours. Water systems must also notify fire departments within two hours of resuming service. The bill allows the use of dynamic information databases, websites, or social media platforms to facilitate notifications. The law takes effect September 1, 2025, unless immediate enactment is approved.