Why does my sump pump make a knocking noise?
Why does my sump pump make a knocking noise? The loud banging noise you hear when the sump pump turns on or off is caused by the check valve. This in turn shuts the check valve, preventing it from flowing back into the pump. The loud banging noise is caused by the sudden change in pressure inside the pump and its hoses. Why does my sump pump make a hammering noise? A sump pump knocking noise or hammering sounds when your sump pump flushes can be solved by the installation of a spring-loaded check valve which is sometimes also called...