US Patent 7757708 Toilet bowl overflow prevention and water conservation system and method

A system and method for conditionally interfering with the operation of a conventional toilet tank fill valve prevents toilet overflow and conserves water. A controller connected to a water level sensor detects abnormal toilet tank water level over time and conditionally interferes with the normal operation of a toilet tank fill valve assembly, thereby preventing a further flush. The overflow and water conservation feature can be designed into a fill valve at time of manufacture and/or added later by a plumber or end user.