Risk of Electrocution?

Not very much, even if you were on a metal ladder or if the aluminum gutter was grounded through the downspout.

There are a couple reasons:

1) Even a short stream of water with high mineral content isn't conductive enough to deliver a lethal amount of current from 220 VAC (or even 440 VAC) service. [1]

2) The stream would have to be unbroken, that is, not a series of droplets, as is generally the case, even with "jet" type nozzles.

[1] Not so if you have the water on your hands and you grab a live wire and a ground at the same time, of course.

=== the line goes to your house ?? YES .... most lines that go into the house have adaquate insulation to prevent such as this problems === wiseman says "" no water hose on lines "" It is a matter of caution .... you did the correct thing to shut off the hose nozzle quickly .... that electrical stuff is very logical and you can replace wall plugs and light switches IF you will just shut off the breaker in the E-panel === check your work by turning on the breaker and using the switch or plug before screwing them back into their boxes ... turn off the breaker after you know it works ,, screw the parts into the box and replace the face plate .. turn on the breaker .....enjoy !!!