When I flush, the toilet tank overfills above the siphon mechanism, which makes a pulsing swishing sound. I turned the water off at the wall, but when I turn it back on, the siphon mechanism makes loud pulsing noises again and the water heater in the closet about 50 feet away makes loud pulsing sounds in the pipes -- until I turn the toilet off at the wall again. The toilet flushes fine.