In order for the CloudRain valves to close and open properly, there are certain requirements for the household's water pressure.
The pressure must be at least 0.5 bar and must not exceed 12 bar. However, in European households this should always be the case.
When using a rain barrel, the water pressure depends on the position (height) of the rain barrel to the valve and the amount in the bin. The use would have to be tried on a case-by-case basis.