Washer, g/d, d/w will dim thelights briefly when turned on

If they are all on the same circuit you are probably looking at an "In Rush" or "Start-up" current that is to large for the circuit.

Are these devices using a 20 amp circuit?

If they are, I would divide the circuit up and make two circuits both 20 amp.

Don is certainly correct,if they are on the same circuit with lights, then the starting current is causing the lights to dim.

If these appliances are not on the same circuit with lights, there is another problem causing the lights to dim that will require an electrician to troubleshoot.