David
I don't know about the other guys but in my case (considering the slow pumps used in brazilian washers) i just have the water from the drain pipes plus the Affinity washer going straight in the sink and then it goes away by the sink's drain.
It's very difficult to have all of them draining exactly at the same time but even if it happens (considering maximum water level for all the machines) the sink will be only 3/4 full.
I also have three floor drains, one automatic machine (and two semi-automatic that drains by gravity) drain directly in the floor drain.
The main pipe is protected by a master valve and I have no independent cold water to each machine. I use T connectors on the solenoids so the machines are interconnected.
My building is 21 floors high and I live on the 6th floor so the pressure is very high. I just notice a pressure reduction when i fill all of the machines at the same time, but nothing so relevant.
Electrically, I have independent wires por each one of the machines (except the two semi automatics that are connected together), independent DR circuit breakers plus an emergency switch (a fire alarm pull station) to shut off everything instantly if necessary.
Probably I'm the only guy in Brazil that use the ground wire. Even being mandatory, everybody ignore this important safety. most people don't even change the outlet, they just break the ground prong on the plugs.
