Originally Posted by Machka

Many campgrounds I've been to have locked toilet blocks. They give a key or a card-key to people who have paid for the sites. And they lock them because someone has thought it would be a good idea to ride into a campground in the middle of the day and stop to use the showers.

If you really want a shower, go to a truck stop or if you don't mind showering outside, go to a beach at a lake or the ocean and use the showers they put there for rinsing the sand off. You can also stop at swimming pools and for the price of a swim, you can shower in the pool showers.