Outside electrical outlet doesn't work after pressure washing
That may not be necessary. You may have tripped a circuit breaker or a GFCI device. 


First see if the breaker to that outlet has been tripped.
If the breaker is not already off, turn off the power to that outlet.
Confirm there is no power on the case by touching a no-contact tester against it.
Carefully remove the cover over the outlet.
Again check there is no power to the wires on the outlet.
See if there is any water in the housing.
If so let it drain, mop up with paper towels, and let air dry.
See if there is any sign of scorching or melted wire or insulation.
If there is, you need to replace the outlet and maybe even some wiring.


Once you are sure it is dry, before you replace the cover, you can try to reset the outlet. All modern outdoor outlets should be GFCI, with a device in the outlet itself, somewhere back downstream on the circuit, or at the main panel. 

Turn the circuit breaker back on, and then find the GFCI device and reset it. This may solve your problem. If not, you may need a new outlet or GFCI device. If there is no GFCI device in the circuit, by all means replace the outdoor outlet with a new one.

If the seals around the outdoor outlet cover are not in good shape, you may want to replace that as well.