Downloadable software for collecting customer data and evaluating, monitoring, alerting and diagnosing issues related to residential and commercial water supply; downloadable software for use in water leak detection, temperature control, filtration, sediment flushing and conservation; water level cut-off switches; control apparatus for controlling water loss from domestic water installations, namely, leak detecting devices consisting of water flow sensor, control unit with processor for comparing regular water flow values to signals provided by a water flow sensor and with audible or visible alarm or transmitter for transmitting an alarm signal, and water valves; control apparatus for monitoring water temperature from residential water installations, namely, temperature detecting devices consisting of temperature sensor, control unit with processor for comparing regular water temperature values to signals provided by a temperature sensor and with audible or visible alarm or transmitter for transmitting an alarm signal, and water valves; control apparatus for monitoring water usage from domestic water installations, namely, water usage devices consisting of water flow sensor, control unit with processor for comparing regular water usage values to signals provided by a water usage sensor and with audible or visible alarm or transmitter for transmitting an alarm signal, and water valves; control apparatus for controlling water loss from residential water installations comprised of water flow sensors, processors for processing signals from water flow sensors, audible and/or visible alarms, stop valves, connection fittings and flanges; differential pressure control systems for water installations comprised of pressure sensors, shut-off valves, computer software and computer hardware