Never running out of water

New Graf Mains-on-tap® water top up unit

The new Graf Mains-on-tap is a clever and cost-conscious solution for the automatic intake of mains water in a rainwater harvesting system. In addition to its simple plug-and-play installation, the Mains-on-tap is impressive with its innovative sensor technology and its quick replenishment rate of 12 litres per minute. 

Graf Mains-on-tap guarantees that even during a dry period, the household is never without water necessary for the toilets or the washing machine, etc., without any manual switching over being necessary. 

The level sensor installed in the tank constantly monitors the fill level in the rainwater tank. If the fill level falls below a critical point, Mains-on-tap tops up the tank with mains water. Compared to a conventional float switch, Graf’s level sensor is far more precise at measuring the water level. Its meticulous control facilitates water use in line with demand, thereby ensuring huge mains water savings in comparison with floating fill level measurement devices.  

The mains water is fed into the rainwater tank by means of a free inflow. The valve allows for a considerably higher flow-rate volume than similar systems: 12 litres per minute in comparison to the industry norm of 5 litres by minute. 

The Mains-on-tap highly compact structure (218 x 277 x 95 mm) and tool-free plug-and-play connection mean that it can be installed in a space-saving way, for example under the sink in the kitchen. 

The Mains-on-tap is one of a number of options that can be incorporated into the proven Graf modular rainwater harvesting system. In this way, up to 50 % reduction in the use of drinking water can be achieved.