New whirlpool wtw6500ww cabrio washer has overflowed with water every load I ran today. What am I doing wrong? It ran over with every size load.

the whole inlet valve must be raplaced

Change the bleach dispenser.

Also make sure the tubes are not slightly clogged from residue build up of mildew.

it sounds like you have a bad touch pad,try unplugging the machine for a few minutes to see if it resets the board,i would call the factory on this,they've been having problems with this and they might give you the part for free but you'll have to pay for the labor.
http://www.repairclinic.com/PartDetail/Touchpad-and-Control-Panel/W10070060/1202650
this could be the problem

Newer machines will eject the water so fast that older home plumbing may be too small to keep it from overflowing. We had no choice but to pay a plumber to install a larger drain to use the new HE washer I bought to replace my old one when the transmission went out. Then I had to fix the drywall after he ran new PVC to the larger drain further down the wall. I suggest asking how big of a hole they are going to make, and being prepared to fix that too.

Check your pressure tube from the base of tub to the control. It may have vibrated loose or gotten a pinhole leak or some sediment inside it. Blow out the tubing and resecure it. I have MORE HERE

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Belt is either broken or may have a nick in it.

this one only has 1 setting on water level. same size uses same level

Your problem is not with the washing machine. I suspect that the drain line for your toilet is obstructed further down the line than your snake can reach. If you have a clean out riser to your sewer system, flush the toilet while someone else is watching the flow past the clean out. I would say that renting a sewer line snake at a tool rental like Home Depot would solve your problem. Good luck

What you can try is to get the machine empty and remove the hose that connects the pressure hose to the switch and blow air through it to make sure it is clear, then tap on the nozzle where the hose connects on the switch to make sure it is also clear.

Great! It may be the water level control switch. So, where is it and how do you check it or fix it or replace it?