Why do water heater make noise after toliet flushes?

Water heaters can make noise after a toilet flush due to changes in water pressure and flow within the Plumbing system. When the toilet is flushed, it creates a sudden demand for water, which can cause the water heater to activate as it replenishes the hot water supply. This activation can lead to sounds like popping or rumbling, often caused by sediment buildup in the tank or the expansion and contraction of metal components. If the noise is persistent or unusual, it may be a sign of a more serious issue that should be investigated.